discontinued??
Sorry to hear that Leupold has discontinued the fixed 6x and 4x scopes, was not aware of same. I abandoned 4x quite a few years ago for 6x, namely the 6x36mm Leupolds. I also run a number of low power variables. But the OP inquired about fixed 4x, so I held off on much more comment.
Regards Simmons, Tasco , Bushnell and vintage Weavers and Redfields for that matter. The made in Japan Tascos and Bushnells weren't terrible, and the Japanese optics industry of the 70's and 80's that put the gold circular inspection sticker on their products, whether scopes, binos or cameras had very high standards according to some light reading I've done on vintage binos. The problem with buying a vintage Japanese Tasco or Bushnell is that there is nothing in place that I am aware of for repair when trouble arises, and with older scopes, sooner or later, you will have a problem if hunted/shot hard enough. Then you are out $50.00+ more for a product that cannot be serviced.
The US Weavers and Redfields can be serviced by a select few private business, the wait period is high, and the cost for same has risen over the years. When you do get your vintage scope back, you will still have a 30-40 yr old optic, that cannot compare to the clarity and resolution of low tier name scopes of today. If I were setting up a vintage rifle for looks and and sentimental reasons, I might invest in vintage Weaver/Redfield glass, but I would not do it for a rifle I intended to hunt and shoot any degree.
Leupold on the other hand, will work on a vintage M8 (or more recent scope) to this day ( I think), and the cost is reasonable and turnaround the same. They no longer offer reticle changes on certain models, but I believe (?) will still service for function, or deal on a comparable scope if beyond repair.