All of the FN-49 stocks have common trigger guard screw spacing, upper inletting is essentially the same, inletting for the trigger guard is different - one inletting scheme for the early TG (used on the Egyptian contract) and another scheme for the late TG (used for later contracts) ... an "early" TG will drop into the late inletting (with gaps) - a "late" TG will NOT drop into early inletting. Then, there are detail differences regarding some minor clearance cuts and of course different inletting for the various butt plates.
Many people have installed 30-06 stocks on Egyptian contract rifles. The modifications required are to deal with:
Crossbolt/recoil lug
Trigger guard rear screw bushing (if necessary)
Safety axis shaft clearance cut (if necessary)
The used 30-06 stocks that are available (take-offs from Belgian contract rifles) will usually have a crossbolt. The Crown-crested Egyptian contract receivers do not have a clearance cut for the crossbolt - you either mill the receiver to clear, remove the crossbolt and plug the holes, or just grind away the crossbolt internally (most people choose the latter).
The rear TG screw bushing sits flush with the upper and lower bedding surfaces on the early stocks. The later 30-06 stocks will usually have the bushing standing proud (above the bedding surface) both upper and lower - the bushing may have to be removed, shortened, and reinserted.
Safety clearance cut. The early TG assemblies had the safety axis shaft (opposite end from the lever) project from the side of the TG - the stock had a clearance cut at this point. Later stocks, inlet for the later TG assembly, did not have this cut.
After you take care of the above items, a 30-06 stock on an Egyptian contract rifle gives you at least an FN-produced walnut stock, but with the wrong buttplate, with the remnants of a crossbolt, and with inletting gaps at the rear and sides of the TG assembly (due to contour differences between the early and later TG assemblies [which have nothing to due with cartridge chambering BTW]).
It's really not hard ...
Goose