Did I buy the correct varnish?

I use W&N Galeria acrylic varnishes.  They airbrush very well, work perfectly and can be cleaned with water,  The one you bought is for oil paintings and not water-soluble.  I personally wouldn't use it, but you can experiment with a junk model.

I think I would rather use acrylic; so I will go ahead and return it instead of experimenting with it. Thank you for your response and time Chrisk-k!

I have used polyurethane varnish, in cans from hardware store, thinned with paint thinner for airbrush.  This was before semi-gloss hobby clear coats became available. Polyurethane varnish is available in gloss, matt, and semi-gloss.  Sure wish Testors would make a semi-matt lacquer to complement its glosscoat and dullcoat.