The original knob you are talking about was only on prototype scopes.
Reliable sources who where there from day one of the Unertl said there were no more than 5 with the football cut on the knob.
The knob on 1015 is likely original.
When I said "original", I meant original to that scope (#1015), which would have had the "football cut" (good description) windage knob when first made. The five prototypes did NOT have football cut windage knobs.
Furthermore, when I said "early production type (knob)", I was refering to the regular, finger-grooved 4.5-MOA windage knob. What I would call the "later production type" would be the 8.5-MOA windage knob that replaced the 4.5-MOA knobs later on (maybe done during the USO refurbs).
This is what I understand from reference sources that are considered reliable, and period photographs and video seem to bear it out:
Peter Senich covered the transitional, "football cut" windage knob well in his book, "The One Round War" (as quoted below), as well as the prototype (of which there were five) and subsequent "production" windage knobs.
There were five prototype scopes built, serial #1001-1005. They had windage knobs that had no finger grooves as we are used to seeing now, and no "football cut", but, rather, a single finger tab as on the fine tune elevation ring. Prototype #1003 is illustrated in "The Long Range War", as well as in "Death From Afar, Vol.1", by Chandler. Unertl's patent #4,247,161, filed 9May79, also shows this first/prototype type of knob.
After these 5 prototypes were approved in 1979, the first lot of 25 contract scopes were shipped to the Marine Corps in March, 1980, serial #1006-1030. Those first 25 contract scopes were the ones that originally had the "transitional" windage knobs with the football cut. The second lot of scopes was not received until January, 1982. This is why you only see football-cut windage knobs in all of the original 1981 magazine articles, Marine Corps Manuals and training films.
"Interestingly, even though the telescope design had been finalized, the initial lot of Unertl scopes (25) furnished to the Marine Corps featured a windage adjustment knob that was still in a transitional state. The windage knob was different in appearance than the Unertl prototype models and was changed again on the production version that followed." -Peter Senich, "The One Round War"
"An illustration from the USMC operation and mainenance manual for the M40A1 sniper rifle and the Unertl scope (TM00539-13/1, 30 November 1981) provides a close view of a transitional model of the 10-power Unertl sniper scope. The telescope shown here was one of the original 25 furnished to the Marine Corps in early 1980. Note the configuration of the windage knob; compare this with the prototype model. The transitional model is also pictured in FMFM 1-3B, SNIPING (28 January 1981). The windage knob was changed on the production version
(see next) of the Unertl sight. For the sake of clarification, there were three versions of the Unertl Sniper Scope: the prototype, transitional, and production models." -Peter Senich, "The One Round War"
"According to Marine Corps information, the second shipment of Unertl scopes did not occur until January 1982. The windage adjustment knob had taken its final form, and from that point forward the telescopic sights furnished to the Marine Corps were categorized as 'regular production'.
"In the absense of an official designation or reference in this case, the original Unertl sights (25) are collectively noted here as the 'transitional model'." -Peter Senich, "The One Round War"
(there's more, but this should suffice)
This scope being auctioned (#1015) falls within the first 25 scopes delivered, in 1980. It would have originally had the "transitional" knob with the football cut. Most, if not all of those knobs were apparently replaced with the finger-grooved "production" type knobs, my guess being probably right after the second lot was received (1982).
