Chris,

 

I'm not sure what it is.  There is no telling what was used, however, I'd suspect that, as you say, it is a standard bearing.  Most likely, but not necessarily, metric.

 

More than likely, there are two caged roller bearings, with a spacer between them. 

 

If you can get one of them out, you should find a number on it.  If not, then you can just measure the OD, ID and width.  Then any bearing company can specify something.

 

There are several on line sources available and well and local industrial bearing sources.

 

Please let us know how you make out.

 

Joe