Below is a post of mine from yesterday under 'Interior' section on the same subject.
If you don't want to do it yourself email this guy below.
He's not cheap, but he is cheaper than snakeoyl
This guy restores mopar seatbelts with the PROPER(matching) inside parts and proper, original stitching patterns.He'll also restore yours.
http://search.ebay.com/_W0QQfgtpZ1QQfrp ... FSQ3aMESOI
If your looking to buy restored ones----
Be careful with some who claim to restore or replace buckle parts.
You must look at the inside parts of the buckle.
The lock assembly HAS to match or the clip will not lock.
If they don't show and describe the inside parts, stay away.