Well, if u have a service manual, and also use the owners manual, you'll probably see somewhere between 25 and 35 different things that are suppose to be done at the first service.
Most of them are just "checks", but there is a point to that. One of them would be checking the torque on the pinch bolts for the front forks. Only mentioning as one example, there are many others. But, ever heard of someone almost losing the front axle because the pinch bolt was torqued properly initially?
If you have the tools etc to do all those things, document what you did and there should be no reason for an mfg to reject a claim. But if you don't, and you don't document it... just pay the dealer. They say the first service is the most important one.
I did my own first service. Man there were quite a few things that were not torqued to specs, rear shock, swing arm bolt, handlebars, etc.