Assuming "slow" speeds means below 1/25 or so, I think you can ignore them for many realistic uses. I have Compurs on which the slow-speed escapement is totally dysfunctional, and it doesn't seem to affect the faster speeds at all.
I don't know about you, but I can't consistently handhold the slow speeds anyway, and if I'm going to carry around a tripod I'm probably using a TLR or large format rather than a folder. I wouldn't worry about it if the camera is otherwise OK.
-NT