First, both my cameras decided to commit suicide within days of each other, so I have no way to take pics.
Anyway, I found a regent 100w merc bucket at restore (missing refractor) and it had a vintage looking 50w HPS lamp in it.
The etch looked pretty old, and it had metal wrapped around each end of the arctube.
It also has no dimple. It looked strangely used, maybe the fixture was converted? (I haven't opened it yet)
Sorry about the lack of pics, my cameras must really hate me...

Sylvania still makes 50w HPS lamps, and all of sylvania's medium base ED17 MH and HPS lack the dimple on top of the outer envelope.

Here ya go

That's almost what it looks like, only the etch looks older. I wish I could post some pictures. 

The HG symbol is a dead giveaway that it's not that old.. that symbol started being used after 2000 I believe.

And it's just like the ones I have, the arc tube isn't centered, but it's nothing a good whack against your hand won't fix.. 

We buy boxes of 30, 50, 70, 100, and 150W Sylvania HPS all the time for my church buildings.  They are still around and they are probably the best HPS out there vs Philips and GE. 

That's a pretty modern bulb.  Mid-2000s or later.  Are there any numbers/letters on the base?

First, both my cameras decided to commit suicide within days of each other, so I have no way to take pics.
Anyway, I found a regent 100w merc bucket at restore (missing refractor) and it had a vintage looking 50w HPS lamp in it.
The etch looked pretty old, and it had metal wrapped around each end of the arctube.
It also has no dimple. It looked strangely used, maybe the fixture was converted? (I haven't opened it yet)
Sorry about the lack of pics, my cameras must really hate me...

If you had one with the spring connected to a dimple, then you'd have something 30+ years old.

The HG symbol is a dead giveaway that it's not that old.. that symbol started being used after 2000 I believe.

2003 or later.