early ones had a rorating lever on the rear of the action and later ones had a sliding safety on the side of the action over the stock.
This link has a list of Sako serial numbers and corresponding dates.
http://thehunterslife.com/forums/showthread.php?t=14777I'm not a Sako expert but looked at a number of them while trying to buy one. Some older ones have a signature on them but have the caliber designation on them ust like a factory barrel. Maybe someone with some more expertise can chime in here.
Mine is a full stock model and is pretty much dedicated to shooting coyotes.
First coyote with it about 10yrs ago
Black Fridays coyote last month
Very accurate and as handi of a calling rifle as you could ask for.