Hommer,
There are a few L-57's in my part of the world, saw a heavy barrel 243 the other day, complete with a nice set of original open sights on it, odd I thought for what would have been considered a "varmint" rifle. Owner wouldn't part with it however, not from my lack of trying I might add!
I have an L-46 in 222 as well, one striking difference I see is the extractors, the L-46 has the longer thinner type of extractor, but the L-57 has the same extractor as modern day Sako's. L-46's had box mags, while the L-57's have an integral staggered magazine with the release inside the front of the trigger bow. Both have the "Model 70" style triggers.
I also have an old L-61, which is now a 35 whelen and a mint P-54 22 LR. Bit keen on old Sako's I am!

DC