The guy who traded this truck in kept his post mount and guages but left the pyro sensor and tube in the truck. There is a 4 wire plug that I pulled through the hole in the post and the boost line is there too. Can I get the guages without the rest of the stuff I already have? Will any guage use 4 wires to work?

 

In short no.
Some gauges don't require any power except for the lighting, a ground and positive, others require 12 volts to run the gauges. It could be the four wire connector you have could be two wires for the lighting and the other two for the pyro. If you can trace the wires down to under the dash and find a box on the wiring the pyro is likely to be the type that requires a specific brand of gauge with it. If there is no box it is likely any non powered pyro will work.
On the boost any gauge will work.

 

It may depend on which brand of gauges that were in there. If you can find that out, you may be able to purchase the missing pieces. Not sure if it would be any cheaper though.