Never underestimate a .22. A well cared for tool will last a long time. I know mine is old, but I haven't searched out the dates yet.
Yours is also a 17 shot version. While they don't have much value, this version is the most sought out of the Glenfield 60"s. Your's will not hold open after the last shot, will dissemble with screws (not push pins) and will work flawlessly as long as it get cleaned and oiled for proper maintenance. (am I correct? )
The sling swivels were an easy add-on, though I have a quick sling just like that one on my Mossberg bolt action. (The fore-stock was too thin to safely add a swivel.)
I would suggest 00 or 000 steel wool and oil to work the barrel back into shape. It will take time, but that is what I used on the 100 year old Sterling-worth I have. (just polishing it for an hour or so while watching TV, or something. The results were worth it.)