Not sure what exactly you are asking.
Do you mean is it possible to print onto any M7 or do you mean can we print for you?
I think you could probably print onto light colours in much the same way as subbing onto polyester shirts.
Inks are expecting to be placed on a white background so colour shift occurs and it's best to stick to single print colours. We use only solid red or black on operation labels / safety signs.
If you are looking for someone to produce for you you might find a local sign firm willing to help.
BTW - the M7 range has just had some new colours added. Metamark will send you a swatch book free of charge.