There was a thread on this a few months ago: https://www.hkpro.com/forum/hk-heads...it-extras.html
The 13e kit is uber rare and one sold for just under $20k. The BPP barrels go for about $1k apiece and HK barrels go for around $5k or more IIRC, so there's ~$25k worth of barrel included. RR 21e's are around $45k. @HkCHUCK priced it all out and came up with $105k.