These rifles were manufactured in various versions and names by Savage, Stevens and Springfield over many years - the stocks, sights and other details changed, but the internals stayed the same. The earliest models could have the bolts removed out the back of the action without dismounting the barreled action from the stock, but later models needed to be dismounted.
The bolt, in semiauto operation, remains back on recoil until you release the trigger, then runs forwards - a bit disconcerting to shooters not expecting it! And as you said, the bolt can be locked forward for 'single shot' use. This improves accuracy, as you don't have the bolt mass moving.
I love my old Springfield Model 87A - a very tight shooter!
Parts if needed are available from Numrich Arms, as they often bought all parts of discontinued guns.