Do YOUR part, the answer is YES.
The camera looks fine, the 50 does too.
The zoom is a matter of taste. For 44 bucks, you're golden. It is an early zoom, and detail nuts hate it. Fashion shooters loved it. Keep it for a pretty but NOT high def images.
You might shoot TMY instead of TX in the Nikon, give it some help. Big difference. TMY and XTOL can threaten your Mamiya's sense of self importance.
way to go