I'm pleasantly shocked that they've managed to get a reprieve here in the UK.
Porterbrook were only sponsors/promoters for the 769s, they're in no way/shape/form an engineering company, it's a coalition of banks and investment holdings - it was Wabtec/Faiveley who did the actual design work and engineering for Flex, Porterbrook then marketed those conversions so they can get further use out of their assets.
As other Desiro operators have shown, they are a 110mph-capable design, albeit with modifications. If this Orion parcels service really takes off, then there may be a need for a small fleet of faster Parcels units to work "trunk" services along main lines in daytime amongst other Intercity traffic. A 110mph unit is going to be more attractive for that than a 319 that can barely reach 100mph. Put a few traction batteries under the 3 unpowered cars (there's plenty of room) and you get some last-mile, self-powering capability for unwired terminals or short/slow forays off OHLE land.
So to answer the OP's question - absolutely, presuming ROG's plans for them are expansion of the Orion operation. Whether it's actually the same design (allegedly) being developed for the 350s, or they go to another engineering firm or technology remains to be seen. But unless they have some open-access passenger operation up their sleeve; or fancy entering the leasing market themselves, I can't see what other use ROG has for them.
There's a lot of ifs, but it all does stack up business-sense wise.
Very best of luck to them!