Go for it. They're a few bucks and you should be able to find one of a suitable form factor to easily retrofit into place.
I 'm not familiar with the model but as you stated 'old' it'll no doubt be pre EN 55011 CISPR 11 era whatever the US eq
If you have equipment with switched mode power supplies they can put guff on the mains. Input filters work both ways and attenuate the guff and transients going onto the line.
Perhaps worth fitting appropriate line filters on other older electrical appliances,