The "Ranger" SxS guns I have seen were Stevens 315's (not 311's). Not saying that is definately what it is (there could be other Stevens models or they may have bought guns from other sources and put their name on them) - would have to see some pics.
I would want to measure the chambers (some around this time were still 2 5/8" rather than 2 3/4") and be sure the lever is right of center when it is locked up (you aren't going to find parts unless you find a donor gun).
Great shape with a cracked stock? $150 for a 12 gauge? $200 for a 16 or 20?
You can get stocks at e-gunparts.com or from gunstocksinc.com