Stained glass chandelier - antique or homemade last month?

I found this at a Goodwill in MA. I am curious whether this might be an antique or if it's just run of the mill. The most appropriate descriptions I've found have been regarding slag glass chandeliers and arts and crafts style stained glass...
How do I know if it is leaded slag glass?
Also, there is an odd detailing on the rim of the metal, kind of a ribbing, which I tried to capture in the close-up shot. That is the only discerning characteristic that I have noticed.
Thank you!