Adding a couple parts doesn't really increase value unless the whole rifle has been gone over by a recognized professional.
Used chassis , 850 - 20%
Used rifle 600 -20%
The uprgrade parts you mention say 300 - 20% , so say 1750.00 - 20% = 1400.00 maximum list price.
Round count and rifle's real time accuracy may move that number up or down 100 bucks or so.
The rifle I listed last week at 1800 shipped in a hard case breaks down like this
Original rifle 600 plus tax/shipping so 650
Minus barrel and original trigger parts , say 500
Krieger barrel 640.00 landed
NM trigger group (gi parts/wolfe springs) 400.00
Usgi bolt guts and wolfe springs 120.00
Sadlak NM guide rod and wolfe spring , 100.00 landed
NM2A rear sights 200.00
Usgi flash hider and front sight 180.00
Minty USGI fiberglass stock and handgaurd 250.00
I'll stop there and not include "gunsmithing by a professional" (450.00)
I've already hit 2300.00 (without a value for smithing attached) and "real" cost including cerakote ect is more like 2600.00.... Listed at 1800.00 with under 100 rounds
Should really be 2000.00 plus shipping but I figured 1800 was a fair price. I've been getting some down right silly offers on that rifle LOL
Just to give you guys an idea on "valuing" a rifle build.