Updated ROM?

[Coucher]

I just purchased a used PPC-6800 Mogul from an individual. As I understand it, WM 6.1 is not "officially" available on the Mogul yet, but there are several hacked/updated ROMs out there which are correct? The phone has WM 6.1 on it, and when powering on in the bottom says "Test Only Not For Sale" and then some red letters/numbers overlayed over it.

I'm guessing that it is an update ROM. Any way to tell which? I would guess those red letters/numbers would indicate which? If I go into the Device Information screen I see the following:

ROM version: 3.49.651.0
ROM date: 04/19/08
Radio version: 3.3910
Protocol version: DCAAXAM-4350H
Hardware version: 0003

And then serveral other things.

I suppose my most important question is, if I can, how do I reset the phone back to the standard Sprint ROM? With the impending official update to 6.1 coming from Sprint in the next month or two, I'd rather have the real deal on the phone.

Thanks in advance!