Nice DeCoster
The spec changed from year to year on the DeCoster so it will depend on what year your frame is. They were available as frame only and in the wheel-less kit form Glynn has shown above and will also have been available from Schwinn resellers with varying complete bike specs.
The DeCoster, although made by mongoose is actually a Schwinn product. Often you will see them with the Schwinn chainwheel as shown in that kit form picture above.
But that has the right kind of look to it that you have there.
The seat would be a messinger not a troxel and would more than likey have had a "Schwinn approved" metal badge on the rear.
The grips you have are one of many types that Schwinn used - the ones you have and the ones in Glynn's pic where both used on Schwinns and were both made by Hunt Wilde - ones you have were called moto-x if i remember right. So all good there.
The gold stem Vs ashtabula stem is a personal preference thing really - both correct.
As it stands personally I'd change the seat for a messinger and maybe keep a look out for some better condition earlier version survivor Union rat trap pedals.
I'd probably go for a set of Schwinn scrambler tryes as well but that's personal preference again.
It's a crackin bike though mate with a real survivor vibe about it - the seat change is the only major one really.
But like i say they also came frame only so it's all good
