The Outbound Laptop Model 125 could use either the Plus ROM or the SE ROM. I think that all of mine use the Plus ROM. It would be interesting to see one which uses the SE ROM to see how Outbound handled the difference.

Of course, Outbound had their own I/O scheme so it could be that the Model 125 just ignored the I/O code, be it Plus or SE, and used its own. The Model 125 has two EEPROMs onboard which provide compatibility boot code and such things as the (IDE) hard drive parameters and such.