I have a number of NOS or near NOS cartridges from when I was a dealer.
A couple after 30 years sound fantastic - as in better than current new $2k cartridges. However most have some attrition, and even though they might track fine, I can hear that the sound has deteriorated.
You records are worth more than the cartridge - I would err on the side of caution and get the EMT serviced.