If the canvas is shiny where there is no ink, it is probably a polyester so should accept acrylic paint without sanding. Only one way to find out – try it.
Paint over parts of the piece with some opaque paint and some transparent pain to see if the paint adheres well and if there is any bleed through of the ink.
If I did it, I’d sand it all down just to rough it up and apply one or two coats of gesso and paint on that.
As an aside, and just my opinion, giclee is a fancy term for inkjet. Usually applied to the use of high end inkjet printers, but these days beautiful prints can be obtained from low end desktop printers, too. Plus, so many artists on eBay and Etsy that print at home use lower end printers and call their method giclee printing, which has really watered down original intent of the term. Anymore, it is, all to often, a term used to try to convince buyers to pay more.
Skill is nothing more than talent practiced relentlessly.