The weight carrying limit on the factory receiver is 500lbs. Yes, you do need a WD hitch with the tongue weight you are considering. Anything over 500lbs would need it. Besides, the WD hitch will make the ride much more comfortable and give you better steering control.
2004 Sunnybrook Titan 30FKS TT
Hensley "Arrow" 1400# hitch
2002 Ford F250 Super Duty, 7.3L PSD Visit our website here
650 pounds of hitch weight on a 3500 truck is nothing. If your hitch says you need one for the tongue things then you need one. But, I would just upgrade the truck's hitch and not bother with the WDH. I pull trailers heavier than that all the time behind 3500 trucks, SRW and dually. I don't have a WDH and don't need one. But, my hitches are rated for the tongue weight.
I know that the hitch wt is a joke on the truck. The problem is the hardware between the two. I have a modest class 3 6000lb adjustable shank setup for moving the empty hybrid around. The reese setup is a little high as well, so I'd have to invest in a 6" drop shank, or just get the upgraded hitch and be done with it all.
Remember guys this is a 1998 truck. It does not have the same cheesy receiver that the 1999-2007 trucks had. In fact, I don't think you could get a FACTORY receiver for the GMT400 platform trucks.
Go out and look at the sticker on the receiver. If the weight-carrying ratings on the receiver are adequate for your camper, then you do NOT need a WDH.
2002 Chevy 3500 DRW 8.1L/Allison
2000 Palomino B1500
...and the reason why I need a DRW to haul a Palomino:
2004 United 7x14 tandem axle enclosed toy trailer
2011 PJ 8x20 7-ton deckover equipment trailer
yes GMT400 trucks came with factory recievers. i would look and see how rusted it is. likely time for a new one anyway. i have thrown a bunch of them away becouse of rust on the side plates, and some for the cross tube. make sure you have one rated for the tongue weight and forgo the wd hitch as that long truck will easily handle the load.
2000 K3500 CCLB DRW 6.5 TURBO
2009 Cougar 320 SRX
2007 atlas 24 auto hauler
1987 GMC origional low miles
With that in mind.....my 96 and 88 K3500's pulling my old 6500 TT with around 650-700 lbs of HW< lost all of 60-80 lbs off the FA. I found there to be no handling issues with just the trailer hooked up.
Now having said that.........I did find that using a std WD setup did help stop some side to side rocking of the trailer in some higher sidewind times, and a dual cam stopped it even more. I pulled that trailer some 50+K miles with no issues be it dead wt or with a WD or the DC, including some 40-50 sidewinds. Not sure about one gust in I405 going across the columbia in east portland. I ended up in the next lane over, as did quite a few other rigs, cars, around me.
If you have a proper strength hitch to handle the overall wt of the trailer, and HW, then the only reason to add the bars is for added safety measures for lack of a better way to put it.
05 Chev CC D/A LS Dooley
92 Navistar dump truck, 7.3L 7 sp, 4.33 gears with a Detroit no spin
00 Chev C2500, V5700, 4L80E, 4.10, base truck, no options!
92 Red-e-haul 12K equipment trailer
3 Single axle utility trailers