Position the contact correctly and solder some solid wire between it and the screw shell to hold it like that while you are working on it. Stuff some high temp & non conductive cement into the hole (but not enough to get to the lamp stem tube inside), shape it and let it dry

Not a big deal. I personally just would solder a length of soft silicone wire to the base contact to run the lamp, in the case it is somewhat valuable.

This has nothing to do with UV exposure, just learn how lamp stem and base are made using something disposable like a regular incandescent lamp.

The lamp obviously is used but looks to be still in workable condition. It all depends on the price paid, of course. If paid $100 for this, I of course will feel cheated, on the other hand something like $10 may be well OK.

I would say return it if the lamp was advertised to be in New condition. Otherwise, mend and repair as needed, but ask for a discount for the defect / damage. My opinion anyway.

Congrats on your new (to you  ) Lifeguard!

I have not been on here much lately but I am still here!  I have a MASSIVE collection and it still keeps growing!
There are several members that are coming to my farm this coming Saturday December 6 for a “swap meet” and to just play with lights.  Kev from UK will be here, as well as a few local/regional collectors in USA.  Y’all please feel free to come.  Text me at (706) 318-8000 for info and address.

Hello everyone. I'm very excited to announce here that I bought today my first, clear mercury vapor lamp, this is a very special lamp as it's an USA made Philips Lifeguard 175W Lamp, made in September 8th, 1986. But oh boy what a surprise it was, when I got home, opened the box [sleeve] and examined the lamp more carefully, and I noticed the beautiful red glass insulator was smashed-looking and had some pieces broken and inside the socket compartment of the lamp; through those holes you can look inside the lamp. I really don't wanna return this lamp as these lamps are very rare in Mexico, and if I were to repair it, I don't wanna diminish its resale value if I were to sell it again way into the future, as these are very special lamps indeed. I highly doubt this lamp is brand new as the arctube looks quite used as you can see from the picture, so I don't have the knowledge whether I bought the lamp and was already like that, or if the insulator got kinda broken on the way home. I was recommended to apply resin on this lamp to repair it. I did hear a little rattling when I got it in a plastic bag, but supposed it was the structural supports rattling inside the bulb. So, what do y'all suggest I do? Also, I doubt any UV will get through, as the broken off parts will be covered by the socket when it's on. I will gladly wait and hear back from what y'all have to say about this.

Oh yes it looks like it

 No . Asbestos has been around for a LOOOOONG time !

Would these predate asbestos though?

Yep !  And as I mentioned earlier , Probably full of asbestos also

 GE Novalux ??