CAT5e is usually 24ga and CAT6 is usually 23ga. If you are using keystone jacks, wall plates are the same. If the plates are combined with jacks, then they are different. The CAT6 jacks are rated higher. You can use a CAT6 jack for CAT5 in most cases. Going the other way puts it out of spec, but isn't usually fatal.

The two are terminated using the same TIA/EIA-568 spec. 568B is the more common (nearly universal) standard.