After trying out citristrip and BLO on a test stock I went ahead and disassembled my new to me No4 Mk1 which had been varnished.
Before, all varnished up:
https://www.milsurps.com/images/impo...4_before-1.jpg
After, stripped and 2 coats of BLO.
https://www.milsurps.com/images/impo...o4_after-1.jpg
It looks much more the part I think !