Hello and welcome to the forum.
I'm a stickler for maintenance and keeping records of everything, most if not all Wing owners take meticulous care of their bikes.
There was a service bulletin for the following: Goldwing GL1800 SB15 2001 to 2008 Trunk Opener Unit.
A well maintained Wing can last for 300,000 miles and beyond.
First, welcome to the forum from Pennsylvania. Sounds like a fair price. Most bugs were worked out by 2005 so there are not a lot of things to check. Like TL said, maint is a biggie. Good luck and if you get it remember to post some pics. Ride safe and enjoy the forum...
These bikes are virtually indestructible!
As long as it has not had major damage in the wreck, you should be good to go.
KBB(which is out of touch with today's reality, in my opinion) lists a 2005 @ $13,375
and w/ABS $13,600.
$10,500 is more in line with todays market.