Ray
The dual-pane windows of your vintage are notorious for seal-creep. I redid one of mine myself. Not a bad job, but a tedious one. I was much too aggressive with the razor blade scraper and badly scratched the glass. I "assumed" that tempered glass would be very scratch resistant. Quite the opposite, it scratches easily. So, if you decide to do-it-yourself, use a good lubricant cleaner to keep from scratching the glass. I had the other windows redone by RVFogDR in Searcy Arkansas. It was a bit expensive (about $200 per window), but they did not scratch up the glass like I did.
Good luck with your window repairs.
Richard