Hi Ejmec,
BSA parts books seem to be available on evil bay etc but you might want to wait until you know the year of bike and model of bike you are rebuilding. In the meantime
www.Draganfly.co.uk have a pretty good set of parts drawings and part numbers online (based on the bsa parts books) for all years of the A10.
One of the most obvious differences between Golden Flashes and Super Rockets/RGS is that they have aluminium cylinder heads and the GF have iron heads, there are many other differences however, and they also "share" most parts of course. As per previous post the best place to start with is with finding the frame and engine numbers and then looking at the info available for that (though it can be a bit confusing!), you can ask for help on here as well, once you have the numbers.
If you are concerned about showing the numbers here just leave off the last digit or similar.