"category" hex values range from 00-04. 05+ reads an error and unlocks nothing.
00 - body
01 - gun
02 - bomb
03 - pod
04 - legs


"Part" values start at 00 with "Standard" and "Basic" parts, and continues in (mostly) the same order as the parts select screen.
Notable changes in the Hex ID order compared to the parts select screen are extra variations of parts being placed at the end of the legal parts' list, and Oil Can/Can always being the first illegal part in its category.

00 bodies: 34 total, ranging from 00 - 21
00 - Ray01
01 - Splendor
02 - Glory
03 - Milky Way
04 - Earth
05 - Sol
06 - Metal Ape
07 - Metal Bear
08 - Metal Ox
09 - Swift
0A - Shrike
0B - Peregrine
0C - Javelin
0D - Glaive
0E - Halberd
0F - Criminal
10 - Buggy
11 - Juggler
12 - Defender
13 - Seeker
14 - Breaker
15 - Seal Head
16 - Dour Head
17 - Tank Head
18 - Ray Legend
19 - Oil Can
1A - Ray Warrior
1B - Rakensen
1C - Ruhiel
1D - Athena
1E - Rahu I
1F - Rahu II
20 - Rahu III
21 - Chickenheart

01 Guns: 52 total, ranging from 00 - 33
00 - Basic
01 - 3-Way
02 - Gatling
03 - Vertical
04 - Sniper
05 - Stun
06 - Hornet
07 - Flame
08 - Dragon
09 - Splash
0A - Left Arc
0B - Right Arc
0C - Shotgun
0D - Rayfall
0E - Bubble
0F - Eagle
10 - V Laser
11 - Magnum
12 - Needle
13 - Starshot
14 - Glider
15 - Homing Star
16 - Trap
17 - Drill
18 - Titan
19 - Claw
1A - Knuckle
1B - Afterburner
1C - Blade
1D - Meteor Storm
1E - Twin Fang
1F - Gravity
20 - Phoenix
21 - Can
22 - Left Pulse
23 - Right Pulse
24 - Sword Storm
25 - Ion
26 - Flare
27 - Left 5-Way
28 - Right 5-Way
29 - Halo
2A - Wave Laser
2B - X Laser
2C - Crystal Strike
2D - Wyrm
2E - Raptor
2F - Waxing Arc
30 - Waning Arc
31 - Rahu I
32 - Rahu II
33 - Rahu III

02 Bombs: 41 total, ranging from 00 - 28
00 - Standard
01 - Standard F
02 - Standard S
03 - Wave
04 - Straight G
05 - Straight S
06 - Straight T
07 - Right Flank H
08 - Left Flank H
09 - Right Wave
0A - Left Wave
0B - Burrow D
0C - Burrow P
0D - Freeze
0E - Tomahawk B
0F - Tomahawk G
10 - Gemini B
11 - Gemini P
12 - Submarine D
13 - Submarine P
14 - Crescent P
15 - Crescent C
16 - Dual
17 - Dual C
18 - Acrobat
19 - Delta
1A - Wall
1B - Smash
1C - Double Mine
1D - Geo Trap
1E - Titan
1F - Can
20 - Standard K
21 - Submarine K
22 - Crescent K
23 - Standard Bomb X
24 - Treble
25 - Wyvern
25 - Waxing Arc
26 - Waning Arc
28 - Grand Cross


03 Pods: 44 total, ranging from 00 - 2B
00 - Standard
01 - Seeker F
02 - Seeker G
03 - Speed D
04 - Speed P
05 - Cockroach G
06 - Cockroach H
07 - Dolphin
08 - Dolphin G
09 - Spider
0A - Spider G
0B - Sky Freeze
0C - Ground Freeze
0D - Feint F
0E - Feint G
0F - Float F
10 - Jumping B
11 - Jumping G
12 - Diving
13 - Wave
14 - Satellite
15 - Satellite H
16 - Beast F
17 - Trio H
18 - Wall
19 - Reflection
1A - Caboose C
1B - Caboose T
1C - Twin Flank F
1D - Twin Flank G
1E - Umbrella
1F - Throwing D
20 - Throwing P
21 - Double Wave
22 - Titan
23 - Can
24 - Standard Pod F
25 - Caboose Pod X
26 - Cheetah
27 - Wolf Spider
28 - Orca
29 - Penumbra I
2A - Penumbra II
2B - Penumbra III

04 Legs: 16 total, ranging from 00 - 0F
00 - Standard
01 - High Jump
02 - Ground
03 - Formula
04 - Stabilizer
05 - Short Thrust
06 - Long Thrust
07 - Quick Jump
08 - Feather
09 - Wide Jump
0A - Can
0B - Booster
0C - Swallow
0D - Raven
0E - Eclipse
0F - Ultimate