You can expect to pay from 300-500 for a 49/56, you want it in the original caliber though of 7.5x54. There are .308 conversions out there that are problematic. Does this rifle come with the accessories kit, 4 mags,bayo,pouches, night sight, French manual, etc. If not, I would try to talk down the price a bit. The original sniper scope and mount sells for around 500 by itself nowadays, the bayo I,ve seen on sites for around 50, mags anywhere from 15-30.
There might be an arsenal rebuild date on the left side of the receiver, thats normal. A capital P in a box with date, like P74 for example, original manufacture date will be on barrel under handguard-----mine was not re-arsenaled, 1962.
Oops!, just looked again and saw the rifle is on GB site, no room for wiggle. No more are coming into the U.S. I paid 500 for mine with the extra's, really enjoy it.
Now about that Sporter MAS36, in one word--------SWEET!! I would enjoy that rifle. Query that rifle configuration on the website I posted, you will get some good knowledge on the history of it and how they came about.