IIRC he ended up, in the final rendition of the bass, installing Mike Lull pups due to the authentic 1960' bird sound they have. I don't know if he considered Thunderbuckers at the time or how they stack up against the Lulls.
There's also this other brand that looks interesting but I don't have any sound info on them...
JPG (Josh Parkin Guitars) Ol' Thunder - Thunderbird pickups Handwound | JPG (Josh Parkin Guitars) | Reverb
So if you're looking for TBird replacements it looks like...
Thunderbuckers
JPG
Lulls
Lollars
SD
Chinabuckers
Eppi VP Probuckers
EMG
Bartolini
Others???
I'd love to see where each of these falls on a sound chart vs the stock modern Gibson pup. Here's my take on the Eppi VP vs Modern Gibby...
Darker<----------------------Modern Gibson--------VP----------->Brighter
Old School<-----VP----------Modern Gibson---------------------->HiFi
Mellow<----------------------Modern Gibson-----------------VP-->Agressive
Thick<--------------------VP-Modern Gibson---------------------->Thin
Mud<-------------------------Modern Gibson---VP---------------->Detailed
If other club members can fill in relative info for the other pups it would be great.