wanting to swap a few 6.1 parts onto my 5.7

If your 5.7 is indeed an 04 truck engine(as per your OG post), it will not have MDS. If the solenoids are present, then you possibly have it. In that case, do as you said. Leave them unplugged and you'll be fine. If you use the solenoid delete plugs, you need to replace lifters. Again, as you stated, those lifters will NOT receive oil pressure if they are MDS lifters and delete plugs are used together.