E35 compatibility

I'm a total noob so easy on the potential roasts.

Background: I have an LMM Engine I'm doing a swap into a 68 IH pickup. The ECM was destroyed in the donor. My question is this: Can I use any "E35" and flash the correct information to run an LMM?
As a concrete example, some Mercedes applications use an E35 ECU. So maybe another way to ask this is whether there are different flavors of E35 that have slightly different hardware and would be incompatible?

If this works, it would open up a lot more hardware to buy on the used market given the scarcity of LMM specific ECUs out there.

You will need your LMM ecm. The architecture is different. We have a number of them in stock, even 1 or 2 new old stock left.