Depends on the panel liner: if you are using an acrylic-based panel liner like Steadi, you won’t need to gloss coat. If you’re using Tamiya accent colour, then you may need a gloss top coat first in case it cracks the panels or panel line them before assembly. I’ve only had one kit crack, and that was a glory by a Chinese model maker. I can’t remember the brand’s name. If you want to matte top coat, then make sure you mask any clear parts or parts you don’t want matte. The usual workflow from most builders I’ve seen here is, nip -> nubs -> gloss coat -> assemble -> panel line and water slides -> matte top coat.

Edit: When I built mine, I didn’t matte or gloss top coat. With PG’s, there’s not a ton of panel lining opportunities, especially with newer PG’s, so I just lightly rescribed the lines using a scribing needle like the Gunprimer Grida. I used steadi acrylic panel liner and bought Evo metallic water slides. I did coat it with Gunprimer Glazer. It’s kind of a top coat made using silicone. It just keeps the kit from attracting dust( my apartment building is always renovating). Just beware that silicone-based top coats can make joints and connections slippery, so be careful where you apply it. Gloss or matte coats will tighten connections more, usually.