Overall I would say that this tripod is good.
What concerns me about the range plate is several things. Firstly, the first column of numbers are butted right up to the dividing line. Secondly the font and size varies i.e. small numbers (1st col), large stretched numbers (2nd col), slightly smaller numbers, so it would appear (3rd column) and the variation continues on the rest of the plate.
My plate and other German plates are consistant and perfectly spaced.
Rivets seem to be overly large and to my mind would be a German sin to overlap the data with the rivets. Also the corners have that clipped look as opposed to a uniform rounded appearance.
Take note of this repro plate:
My plate on the left and another on the right confirmed as German:
The bolt box is correct for an MG42. The characteristic of a '42 box are the two rivets, close together and off-set, for a single leaf spring to retain the bolt. The '34 box had two rivets either side of the box latch to affix a double ended leaf spring.
Concerning parts that are painted and unpainted then it is perfectly consistant that the tripod was factory painted in Gelb. If it was painted in the factory then it would explain why the weapon lock/release, buffer and other parts are in a raw state, so to speak. This was standard practice.
Red oxide, I think, can be seen where the MG's lugs drop in. The possible reason why red oxide can be seem in this area is because it is exposed to a compressive wear from the lugs whereas all other parts/surfaces are subject to lateral wear which would be more damaging.
The date I think is a '43' because everything adds up i.e. factory Gelb paint, 42 tripod, 42 bolt box - everything adds up to latter war 43 date and not 1940. Also, I think the right hand, mid point of the digit appears to turn in as a number 3 would but not on the left side.
I think the pads have been replaced at some point as they don't look age or leather correct.
Wear and tear seems correct, belt wear, spent case ejection, everyday wear etc etc and indeed it does not have that new look e.g. bright steel. Of course, a bit of imagination and a year or so in a damp barn will also do the same.
What would be nice, if your able to get them, is to have photos and/or info on the rest of the codings and stampings. The markings on the T&E unit, markings top left of the main A-frame, maker stamp on the top hinge of the front leg, maker stamp on front lug of front leg adjuster, maker stamps on top of inner cradle bearing bolts (if any) and traverse limiters (if any).
Tom.