FWIW, the last Service Grade I got has a CMP certificate from Sept 2020. It's was mixmaster Winchester with a 1951 SA barrel (TE was 2+, MW 1) along with a WRA trigger housing and trigger guard, with mixed SA parts. I suspect it was likely a Philippine return based on the rack markings on the wood and overall slightly worn condition (see lower band below) that meets, but did not exceed, CMP's Service Grade criteria.
Dissembled. No pitting under the woodline, but very superficial blemishes/oxidation on the heel and some pitting on the rear sight cover. The wood was rougher than I like, no markings except a faint P on the pistol grip....but it was a WRA with a pretty nice heel stamp from May 1943.
Replaced the generic and somewhat rough USGI wood with a nicer post-war USGI stock with DAS cartouche, also used some extra Winchester
parts I had set aside over the years, such as an 1967 dated Winchester "script" barrel, WRA bolt, op rod, hammer and lower band. The surface blemishes on the heel bothered me, so I re-parked the receiver, bolt, and rear sight base at my buddie's house this past winter:
Here's the 'after pic' with nicer USGI wood, a few extra WRA parts (but still very much a post-war rebuilt mix-master), along with a vintage web sling:
Metal finish after manganese-based reparking. (The rear sight cover was replaced with one that lacked any pitting). I was reluctant to refinish the receiver etc, but it had already been re-parked with I think a zinc-based finish at some point in the past, so I decided to lightly restore its appearance.
...so Service Grades can vary a lot, and might not be quite as nice as what was sold 6 or 7 years ago, but still a good value and very functional - and of course a historic firearm. IMO folks interested in vintage US military arms should own one service grade type of M1 Garand, if possible.