According to my very old and trusty Gun Parts catalog, your're spot on in your guess, NeedAclip.
It showns the rifle as being a:
House Brand Sears M5,M-5T;
Model# 273.2341;
Orig. Mfgr. Winchester;
Orig. Model 150-250.
Google Search for- Winchester Model 150
www.google.com/search?q=Winchester+model+150+&hl=en&lr=&ie=UTF-8&oe=UTF-8&start=0&sa=NRifle Stocks-
m1.aol.com/custstock/Winchester.htmlObsolete Parts-
www.usracmfg.com/obsolete.htmGood luck and enjoy your Dad's gun.
I recently happened to acquire my Dad's .22 that is a Winchester bolt-action 'J.C.Higgins' made by Marlin as a model 81; it's currently getting the stock refinished.
Then, in one week, I got my late Dad's post-64 .30-30 Winchester model 94 in rough condition AND my late Step Dad's pre-64 .30-30 Winchester model 94 in good condition!
I can't believe my good fortune.
The post-64 is gonna be upgraded in the refit.
The pre-64 will remain in original condition.
Anyone getting a family heirloom is in for a real treat.
Have fun.