I'm heading to Merope 2A to check if I can scan an intact barnacle and get a result.
You can scan an intact barnacle, but still get "data corrupted". During my verification run in Witch Head Sector, I scanned all seven barnacles in the six locations, and now have about 740 kCr worth of Barnacle Scan Data in my transactions tab, which will pay for my running costs. Scanning a barnacle twice or the second dome of a double barnacle will give an "Alert! Organic Structure already scanned" message. This looks to reset itself after some time, I scanned the two barnacles discovered by Midnight Ninja on Witch Head Sector GW-W c1-4 A 4 a week ago, got a scan data package, and sold that. This week, I was able to scan them again, and got another data package. I have not tried if scumming allows further scans, or if you can travel back and forth between the barnacle and a station and get several payouts per week this way.
Let me check my notes:
Witch Head Sector LC-V c2-10 A 4, -16.5359/151.8175, d12nd, scan value 126486 (previously scanned)
Witch Head Sector LC-V c2-10 A 6, -24.4643/-26.8704, d12nd, scan value 74328 (new find by Kerevan, first scan)
Witch Head Sector LC-V c2-10 B 1, 4.0266/-40.0450, d12nd, scan value 195566 (new find by Kerevan, first scan)
Witch Head Sector LC-V c2-10 B 2, -0.5026/-163.3102, d12nd, scan value 151538 (new find by Kerevan, first scan)
Witch Head Sector GW-W c1-4 A 4, -65.9886/-173.642, d24nd, scan value 50168 (previously scanned)
Witch Head Sector GW-W c1-4 A 4, -24.8372/-119.8862, i12nd, scan value 112037 (previously scanned)
The only double barnacle left in Witch Head Sector gave the lowest payout, and the only intact one is just in
third fourth place.
Scanning intact spikes will not give a monetary reward, but will inform you what minerals are in there. Destroyed spikes cannot be scanned.