No. Rigs paying more on your regular trips will pay first year rates.

Anything you pick up from OT will pay second year rates providing you're at or over your original line value.

For example if a reserve pilot's original line has 90 TFP, but due to rigs and trip credit ends up paying 120, he'll get first year pay for 120 trips. Now, suppose you pick up another reserve block from OT... now anything you fly during that reserve block will pay second year rate. Same if you pick up a trip in OT.