I realized I'm being long-winded so here's the TL;DR: abolutely, if you feel fine then it's fine. Gear is only required to the extend that you need the stat, and it's up to you to decide your needs.
--original long-winded reply below--
That's because you are comparing them to unmelded 290HQ. Each 290HQ accessory has one slot that can easily take a +10 Gathering or +6 Gathering if you want to go cheap, and you end up with +60-20=40 more Gathering or +36-20=16 more Gathering and the extra 20GP over your level 60 pieces.
But the real value of the 290HQ pieces come from overmelding. You can easily go for +6 GP +6 Gathering +6 Gathering on each piece of accessory, giving you a total of 6x6=36+20=56 extra GP and (6+6)x6=72 extra Gathering over your level 60 pieces.
Of course, you can keep using the level 60 pieces if you haven't run into situations where you want more stats. But when you start gathering folklore nodes and doing aetherial reduction, it's also possible that you'll find yourself looking to get that 700GP and those extra stats to boost your gathering efficiency. Not to mention you absolutely need about 1143 Perception if you want to gather HQ folklore mats yourself, and it's probably impossible to get to that threshold with those level 60 pieces.
Obviously if you are taking it real casual and only aim to get those pretty yellow scrip sets, then yeah you probably can survive without upgrading. I tried yellow scrip farming with my level 60 crafted HQ gear that gave me also close to 900/900 stat, but I couldn't bear the inefficiencies I was suffering, so in the end I bought a full set of 290HQ tools, armor and accessories to farm my yellow scrip. I did it because I knew I need the 290HQ set anyway, since I was going to give the yellow scrip gathering sets to my retainers.