Ok here is my update and it should also answer your question.
I chickend out at the last second, called up a rep at the DELL DCS team, who told me that my current bios 1.47 is a specific DCS BIOS, and that since the ESM is soddered on and not socketed, that doing ANYTHING to it will brick it.
So....those 2 DCS nodes are being shipped back to seller ,and seller is shipping me back some service tagged nodes.
To answer your question DooFoo,
Yes you can upgrade your nodes, using the bootable USB DOS method, make sure to download the 6100v170.rom and use AFUDOS to flash it from DOS.
The reason i say this, is because it doesnt so much matter what the chassis is as long as you are able to bring up your Service taggs on the nodes, and in this case it appears you can actually SEE your service tags in your bios, which means your a step ahead of me.
So, with that in mind as long as you can bring up the drivers for your service tag, which is sound like you did, you are good to go.
You can flash your BMC by going into MAINTENANCE MODE from the remote management service via your network. you will possibly want to consider the latest 1.33 which you will only find on your dell driver list after inserting your tag.
Be sure to use the Bootable DOS USB method with AFUDOS
The command will be the following:
at which point it will bypass the SLP HOL protection, and skip the rom check, while forcing the update on your system.
This worked out perfectly for me, after following the guys on this thread here where I learned about it:
http://forums.servethehome.com/processors-motherboards/1707-dell-c6100-xs23-ty3-firmware-updated-2.html#post16371