The NP205 will bolt right up if it is a 32 spline 6 bolt round pattern case. You will, however, need to figure out how to hook the transfer case shifter up as the NV4500's tailhousing does not have the tapped hole for the big shifter bolt like the SM465 has. One option here would be to make the switch to a twin stick shifter setup which uses shifter cables instead of bolting up to the big bolt shift assembly.
I'd personally opt out from the 205 and switch to an NP208 or NP241 myself, but that would involve a new driveshafts whereas keeping the 205 would mean that stuff would stay the same. You may need a new transmission crossmember from a newer automatic truck if it uses the old puck style transmission mounts vs the single mount.
The NV4500 will use the same clutch as the SM465. Make sure you use the correct clutch fork however, the SM465 part is not the same. The external slave bellhousing will not work very well on a stock height truck. The slave sits on the passenger side and the driveshaft will hit it. Internal slave is a bolt on swap with a new input shaft retainer. You can use a stock 85-87(91) master cylinder with both the internal and external NV4500 slave cylinders and just make an -AN braided clutch hose to connect them together. There are adapters for both the master and slave cylinders to convert them to -AN fittings.
Your floor shifter hole will need to be modified. The shifter on the NV4500 sits a couple inches further back closer to the seat than the SM465 does. The SM465 wiring will plug directly into the NV4500.
All in all a fairly simple swap. You'll need to source the internal slave bellhousing and input shaft bearing retainer along with a set of hydro pedals with a master cylinder, a few clutch hose adapters and braided tubing.
