Our 1960 Series 2 Land Rover, which had spent 20 years in the Australian Army, 15 years on a farm, and then 15+ years broken in a field and then a back yard, still had the original army seating in the front, complete with two cigarette burns, which I personally liked because it added a bit of history to her. 
Sadly, these were very uncomfortable and to replace the foam would have ripped the old fabric, so it was time for new seats. 

A quick look around the internet found 'standard' seats and 'deluxe' seats, which based on reviews, were apparently more comfortable.  Installing BritPart Deluxe seats was super easy and only required the following:

• Britpart Seats (Details Here)
• 6 x M6 (30mm) bolts and washers (Britpart Seats are metric bolts)
• Six rubber door stops
• About one hour of time

Installation Video