One of them looks like the holes for the seat frame mountings but it's been a while since I looked under my carpet.
I'd fit the grommets unless you have refitted the moulded carpet. (unlikely) I drove without the floor grommets in heavy rain and water came up through the floor. Damp carpet doesn't smell too nice. Then again my 7 still smells of waxoyl. If you're worried about moisture with grommets fitted you can always lift up the carpet section to check periodically.
I never bothered with the grommets in spare wheel well. There's nothing for moisture to soak into and it flows out again.
Adam
TR7 V8 DHC Jaguar Solent Blue. 9.35cr Range Rover V8, Holley 390cfm, JWR Dual Port, 214 Cam, Lumention, Tubular Manifolds, S/S Single Pipe Exh, 3.08 Rear, 200lb Spax & PolyBushes all round, Anti- Dive, Strut-Top Roller Bearings, Capri Vented Discs & Calipers, Braided Hoses, 4 Speed Rear Cylinders, Uprated Master Cylinder & Servo, AT 5 Spokes and Cruise Lights, S/S Heater Pipes, Replacement Fuel Tank. No Door Stickers. Mine since July 1986, V8 from 1991