yes It should. I have never turned a Roman Harvest pen, But the pilot G2 should be the same as a standard refill. I have used them in Jr Gent pens before, and they worked fine.
Yes, they work just fine. AND the G2 gels are permanent ink that can't be acetone "washed". I keep a few G2 5s and 7s in the show box, because those refills have a devoted following here.
Acetone washing is a "trick" that check forgers use. They'll change the name and dolla amount on a legitimately written check to their assumed name and a much larger dollar amount.
"Check Washers" helped to quickly speed up the transition from checks to debit cards. A few years ago, check washing was a major source of check fraud and identity theft.