Mini Series Number/Year
ChartNote Instruction Manual button at top right. Make sure you get correct manual for your particular Mini.
Wide selection of wood/laminated/syn stocks and handguards at
Accuracy Systems Inc.ASI link above is not exhaustive, so do shop around for other options and prices.
Personally, I would choose a syn stock over wood or laminate, but that's my choice, YMMV.
If choosing wood, I'd opt for Birch, since it is a little denser, and less likely to crack/split compared to Walnut.
The period-correct stock for your Mini likely had a
curved butt plate usually of plastic. Many users have bought
replacement stainless steel curved butt plate from Gunparts, done a little fitting, then painted them to match the gun. The advantage of the stainless steel version is that it can be easily re-painted when--not if-- it becomes badly scratched, and no rust. These steel butt plates come and go, and the blued version is "Out of Stock". Suggest getting one now, instead of waiting.
Modern Mini stocks have a straight rubber compound butt plate. There are also some differences in length-of-pull between the old-style and new-style stocks.
There are some people who feel that wooden stocks on many early Minis were cut to fit very loosely and this negatively impacts accuracy unless the wooden stock is shimmed and/or bedded.
OTOH, syn stocks
generally have a tighter fit, and are not susceptible to moisture induces warping. Laminate stocks somewhere in between, being heavier than either simple wood or syn stocks.
Any stock can be "massaged" to work well, but some take more work than others, and some are heavier than others.