I voted. As if it should be a poll, but I have some advice for you on "package deals". They generally don't go over as well as selling things separately. Next....ammo at good prices is selling now. Pistols at area/condition prices are also selling now. Holsters...well....they are more of a personal item if you know what I mean. Most of us never started carrying with a 'package'. We continually customize things to fit our lifestyles. Consider the holster as a 'give me' item in your for sale total. Just like night sights, and extras such as more than two magazines, or fingertip extensions and the like. Some accessories may sweeten the pot for a sale, but you'll be catering to a smaller crowd. Your pistol alone (even used), could sell (under the right circumstances) for your $600 asking price. This depends on several things. I believe I paid $610 OTD on a brand new G30 with factory night sights when they first came out. I am still in awe at the G36 because I've never owned one, and I see very few of them in gun shops or at gun shows. Extra magazines for it don't seem to be in proliferation either, and holster choices are likely a lot less than the mainstream Glocks. Now...understand that I would probably like to have a G36 new or used, but pending the purchase of a new G26 for my wife (for Christmas)...I'm not in the market for one now anyway. But here's my best advice (and depending on where you list it for sale). You're going to get lowball bids no matter what you're selling these days, so make up your mind as to what you would take bottom dollar on the pistol alone, then post it +$50, and expect to get an offer of $25 less on your first contact if not more. While working a likely deal, use some of (but not all unless they ask) the ammo in order to get what you want out of it. List the holster on EBay (and I see a lot of them there, especially the Blackhawk Serpas but again....not many accessories for the G36). Keeping it all in mind, I'm sure you can get your average $600 total asking price if things sold separate no problem. As a package deal, I think it will be more difficult.
You can buy a used Glock for $350 to $400 dollars if you shop around. I wouldn't pay $600 for it no matter how nice it looks. I could buy new at that price.
You don't see many used G36s for sale no matter where you look, and the used price range of the mainstream Glocks likely follow your equation, but the 45acp caliber Glocks, and especially the G36 do seem to demand a higher price on average than the 9mm, 40S&W, and the 357sig pistols just because they are more limited on parts interchangeability and a few other factors we don't usually consider.
I'm just saying......this was in the advice column of today's headlines, and I've given mine.