Johnny, Sounds like your off to a really good start.
A 38 Dodge truck has a pretty tight interior, if you are not concerned about originality of the seat, the 2nd row bench seat in a mini van fits pretty good, you need a seat that sits pretty upright rather then recline a bit. You loose too much cab space with a seat that leans back too far. The next option would probably be a pair of bucket seats, again I like the minivan second row buckets. they sit more upright, most have backs the tilt forward, and most have most of the seat belt attached to the seats. Mini van seats are pretty easy to find in really good shape in pick and pulls, for pretty cheap.

The hood ornament may be a challenge, and might be expensive. Many of that era pickup trucks were sold without rear bumpers, most went to farmers and they built their own. Tail light brackets are pretty generic, but repo tail lights are available. Shop around, prices are all over the board.

If you have a Cuda 8 3/4 laying around, I wouldn't hesitate on using it under your truck. Other options have many drawbacks.

A google search for "38 Dodge pickup parts" will net you some parts sources. Also, www.robertsmotorparts.com, and www,vicsgarage.com are a couple more. Don't overlook LMC trucks either. Gene