Even easier. Go to Stockinteriors.com. and check out covers for 79 to 83 Dodge trucks. The bench seat cover will fit the crewcab bench. One section wraps around differently than the original design but it's invisible and pretty self explanatory..
Then check their listing for Ramcharger buckets. They probably offer matching material for both sets.

Matching seat covers for mismatched seats doesn't get any easier.

Also, go ahead and order carpet, strongly recommend the mass backing for noise reduction.