Des Plaines OSA804 (probably, can't find one in the package at the moment) gp38-2 screens:
Des Plaines OSA849 gp38-2 radiator fan hatch:
The OSA radiator screen is for the later phase gp38-2's, where the radiator fans are moved close together, and the radiator screen is a single panel. The MTH model looks like this configuration, so there is hope that the OSA screen will work.
Jim