I've got a couple custom Glocks and they are for me to enjoy. The added parts on mine are worth the extra money I paid-flat trigger,mag. release, internal parts/springs and barrel make a big difference. The aftermarket barrels allow you to shoot lead/reloads, if you do that. ZEV makes a great barrel but there are others out there that make quality barrels for less-Stormlake, Alpha Wolf,etc.. The stippling can be expensive and to me, makes a big deal with gripping. There are some dealers out there that do a good job and you will be amazed at how much better it feels in the hand but it will cost you depending on what is done. That frame has some good stippling and the trigger undercut can be appreciated after a day of shooting.
As far as reselling the parts and what you would get, depends. If it is a ZEV barrel,probably around $100.00 -125.00. The slide might get you $300.00 if it is cut for a rmr, ( a real Trijicon RMR will cost you $350.00-400.00 easy). The frame could be worth around $175.00-250.00 depending on the buyer. It is hard to tell in the pics if it has a ZEV trigger and internals. A ZEV trigger can resell for around $80.00-100.00. If it has night sights, that can add around $70.00 or maybe more. On the low side of things, The pistol would be worth roughly $750.00 to $900.00,without the holster and light,in my opinion. The holster and light can add more value to it. Holsters are usually a personal thing and most don't have much resell value for the most part. The added light,depending on if it is a quality light could add another $70.00 - 100.00 to the deal.
I sold a Glock 34 with some ZEV parts-ZEV 34 slide with Stormlake barrel,suppressor height night sights,standard Glock frame with no ZEV parts but it did have a ZEV brass magwell for $750.00. I didn't have much more than that into it and the buyer was happy and so was I. Depending on what computer you have and what it will be worth in the next year or so, it might not be a bad deal for you. Just my 2 cents