Contact Daimler-Chrysler, they can tell you how many were produced.
I did that with my Designo SLK, and they said there were 127 of them imorted and sold in model year 2000.

 

Will do thanks......

 

That's a niiiice truck, I'd almost pay way over blue book for that, I'm sure I'd pay some over without hesitation.

Unfortunately, tempting as after market products might sound, I would keep this thing as stock original and 'as is.'
I really think after market stuff would be like putting make-up on a natural beauty, might even lower the value of the vehicle. The trans cooler I'm ok with, one thing you might do is play it safe and, if you do the K&N filter or other such things, make sure you keep all the OEM parts someplace safe for years down the road.

I'd check the oil and all the fluids, replace the air filter just for kicks, maybe have the trans fluid and filter replaced...
And, if as I suspect, all the fluids and everything checks out, you can probably safely assume it has been properly maintained and just keep up on it. Because I think so long it runs fine I wouldn't be for fixing too much, if for no other reason than if it ain't broke...