AFAIK, any modern canti brakes should fit on any modern canti post mount. E.g. I've installed new Shimano cantis
on a 1980s cyclocross fork without any problems at all.
The two main problems you might encounter are:
1) You have to make sure your brake levers are for cantis and not v-brakes. V brake levers have a different cable
pull and won't work for cantis (I am sure you know this aleady, but it's obviously worth repeating).
2) Some modern cantilevers have a wide profile that can cause you to catch your shoes on the brakes when dismounting.
Already a problem with cyclocross frames, it might be a bit more so on an MTB frame with wider seatstays.
Johnny