Is there any way to check whether a given r-code file is 32 bit or 64 bit?

The OpenEdge 10.1x and 10.2x series use different r-code formats for 32-bit and 64-bit r-code.
Running 32-bit r-code in a 64-bit client or vice-versa will result in an error "Invalid version, <version> (expected <version>) in object file <file-name>. (2888)"
(version over 16000 = 64-bit, lower = 32-bit)
Is there any way to check whether a given r-code file is 32 bit or 64 bit?

There are no utilities or specific ABL features that can determine whether a given r-code file is 32-bit or 64-bit independent of the bit-level of the client used.

Upgrade to OpenEdge 11.0 or later.
Starting with that release, a unified r-code format is used which is portable between the different bit-levels. This removes the need to distinguish between bit-levels, meaning this enhancement is no longer needed.

Try running the .r files from a client with a known bit-level. If the bit-levels match, the r-code will load. If not the  "Invalid version, <version> (expected <version>) in object file <file-name>. (2888)" error will occur.

If the (2888) error is seen, the bit-level can be inferred from the version numbers listed: 
If the version number is over 15000, that indicates the 64-bit format, otherwise it's the 32-bit format.

Example, the error reads "Invalid version, 17391 (expected 1005) in object file myfile.r. (2888)".
In this case, the 17391 is the version found in the .r file, so this is in 64-bit format. The client is a 32-bit client as it expects the 32-bit format.