Apart for the previous observations, the presence of a steel back probably implies the case it is gold filled.
Which is rarely an attractive option , particularly in such a badly reprinted watch.
You are correct in suggesting that the OPs watch is not solid gold.
Constellations are gold-capped which, whilst not solid gold, is a very different animal to gold-filled.
If I'm not mistaken, this one looks to be rose-gold and they are very attractive and I have one myself (but with the correct pencil hands)
However, the issues with this watch would make it a strong pass for me.