The right amber lens appears to be available; but, the left amber lens appears to have fallen into the unobtanium status. Skandix, GCP and Scandcar all list the left as unavailable and if they don't have it that generally means new ones are unavailable.

These guys list it
Volvo 140 160 Parkeerglas USA L - 680023 [Volvo-680023] - €30.00 : Classic Car Parts, vintage, classic and youngtimer parts (classic-car-parts.nl)

I have never dealt with them (or heard of them) so cannot advise as to whether they are a reliable vendor.

If you want new, I think converting both to clear would be the smart way to go if you do not want to pay a nosebleed price for a salvaged one.

 

I paid nosebleed for my left and right pair back about 4 years ago.. and the second issue that arose after that was getting a left rubber that wasn't dry rotten or burnt. I was never able to source one from any of the known suppliers but came across a fella on facebook who 3D prints them from a flexible material and they work nicely for what it is. FYI prior to that I had ordered that 68-70 spec rubber from suppliers and received a '71/'72' one so if you do find anything related to those ambers or early series lenses/rubbers then be prepared for the possibility of them being incorrect.