I'm dumping my save file right now so I have something current to look at, and will continue with that once I get the memory addresses sorted out.
Data Structure is as follows:
00 00 00 36 = weapon ID (Ghirrahim Demon Blade leve 1)
00 50 = Weapon Base Strength
00 01 = Weapon Stars
11 11 11 11 = Slot 1 Information (00 00 00 03 = Strength 3)
22 22 22 22 = Slot 2
33 33 33 33 = Slot 3
44 44 44 44 = Slot 4
55 55 55 55 = Slot 5
66 66 66 66 = Slot 6
77 77 77 77 = Slot 7
88 88 88 88 = Slot 8
99 99 99 99 = Kills to Unlock Slot 1
AA AA AA AA = Kills to Unlock Slot 2
BB BB BB BB = Kills to Unlock Slot 3
CC CC CC CC = Kills to Unlock Slot 4
DD DD DD DD = Kills to Unlock Slot 5
EE EE EE EE = Kills to Unlock Slot 6
FF FF FF FF = Kills to Unlock Slot 7
10 10 10 10 = Kills to Unlock Slot 8
03 00 00 00 = Weapon Identifier (See Pastebin)
Not quite. The weapon identifier (I used the term type) is at the start of the structure, not the end. So the data starts at 0x8D74C (and the last structure starts at 0xA08C8)
I've spent my evening building and verifying a spreadsheet to translate the raw data into readable info. I haven't verified every weapon in my file but those I have are all correct. I made extensive use of ScarletKohaku's pastebin, but also doing some text dumps from the game files because the strings always seem to be listed in the correct ascending order for the relevant Weapon/Skill IDs.
Haven't figured how best to document it all for this post though.
https://drive.google.com/file/d/0B0YIN5YdJt0GVGM4bElsMzFjM0k/view?usp=sharing
If you're looking to insert your own data into the sheet for browsing purposes you need to get the hex values for the range 0x8D74C - 0x9189B exported as plain text with tabs between each byte and line-wrapped every 76 bytes (see the attached for an example). Once that's done it'll paste into Excel or LibreOffice with each byte going into the correct cell.
Ignore the 3DS portions of the sheet for now, it's incomplete, more curiosity than anything, and probably incorrect.
Edit: Thanks for the items, added to the first post. Regarding the missing spaces I gaps seem to mostly match up to 'missing' items from the original Adventure Map list that aren't included in the Twilight/Termina maps.