Just to clarify...
The rails are standard width on the CA, no issues there, as is the actual height of the rail attachment itself. But the overall rail height is different due to Classic Army upper receivers being slightly taller than TM and others. When you mount a railed front end, other than CA brand, you will more than likely see a height difference between the receivers top rail, and the top rail of your RIS/RAS system. It seems to be about 2mm or 3mm.
This is why many people wanting to mount a CASV on their CA's are usually SOL, since the extended top rail needs to be at the same level in order to mate properly with the rail on top of the receiver. In the end, unless you plan to mount optics on the top rail which may straddle both the front end and receiver there won't be any issues.