First off, North Cape Publishing is riddled with errors. The one and only book you seek is called
“Crown Jewels - The Mauser in Sweden: A Century of Accuracy & Precision by Dana Jones”
So the Swedes had a lovely case of attention to detail sprinkled with a severe case of consistency in all...
Here is a BRNO 537 rifle that is very reminiscent of a Vz.54/91. If you look at the shape of the stock in the wrist, palm swell, buttstock, even the butt pad. Appears to be a heavy barreled action in 7.62. I can't seem to find pictures of anything similar.
That’s good to know. I’m building a first issue M40A3 with big hook stock, unertl, and side bolt release. I’d be interested to see what kind of info you have on the early M40A3s.