I was planning on purchasing a Seiko SARB033 as my first watch, but this Constellation has caught my eye. Are there any obvious issues? Is that case back original?

I have not seen an abundance of Constellations with that particular watch face. The location of "quartz" immediately underneath the Omega seems uncommon. Is it legitimate?

 

Welcome to the forum, @AndyZ. I do not know this particular Constellation model, but there is a much higher likelihood of responses if you post your questions on the following sections of this forum:

For Vintage (pre-80s): https://omegaforums.net/forums/vintage-omega-watches-help-discussion-and-advice.23/
Modern: https://omegaforums.net/forums/modern-omega-watches/

All the best...

 

If this is from South Korea it is highly likely a redial.

And far be it from me to inquire, why go for quartz when a mechanical can be had and will provide more pleasure?

 

It's genuine and from the mid-late 70's. Not a cheap watch at the time, because Quartz was 'de rigeur'. Case width is small at 32mm

 

There is a shop in LOs Angeles with those dials also. This is not one of them.

 

I wuold pass it.