For them as cares, Fafhrd & The Grey Mouser were completely statted out in the original
Deities and Demigods for 1e (the one with the Melnibonean & Nehwonian Mythoi).
Fafhrd (Hero):
AC: 2 (18, in 3e)
Move: 12 (30, in 3e)
HP: 120
Size: M (6' 11")
Alignment: NG
15th level Ranger, 13th level Thief, 5th level Bard (but remember that he's 1e, so this only makes him 15th level. Also, since this book predates
Unearthed Arcana, there WAS no Barbarian class, at this pont!)
STR: 18/00 (+3/+6) INT: 17 WIS: 14 DEX: 18 CON: 18 CHA: 17
Notes: Speaks/Reads/Writes all the major languages of Nehwon, and has an 80% chance to understand any esoteric ones (High Decipher Script, in 3e).
Graywand is a Bastard Sword. Heartseeker is more a poiniard or shortsword. He also sometimes uses a handaxe balanced for throwing, and a longbow (Masterwork Mighty Composite, in 3e).
He gets +20% Climb & Hide over the 1e base (no reason given).
The Grey Mouser (Hero):
AC: 2 (18 in 3e)
Move: 12 (30 in 3e)
HP: 96
Size: M (5' 3")
Alignment: Neutral
11th level Fighter, 3rd level Magic User, 15th level Thief (but, again, in 1e he is only 15th level)!
STR: 16 (+0/+1) INT: 18 WIS: 14 DEX: 19 CON: 17 CHA: 18
Notes: Scalpel is a rapier, and Cat's Claw a dagger balanced for throwing.
ALSO, T$R put out a whole series of Lankhmar books, way back in the day, including much of the info posted in AFGNCAAP's post, above. The only one I ever bought was the first one,
Lankhmar, City of Adventure. Naturally, this book lists completely different stats for the heroes!
Fafhrd:
Ranger 15/Thief 5/Bard 5 at his peak,
R 10/T 3/B 4 at maturity,
R5/T1/B3 as a youth.
Alignment still NG
STR 18/75 (+2/+3)
INT 15
WIS 10
DEX 17
CON 19
CHA 17
AC 6 (14 in 3e)
HPL 130 Peak, 110 Mature, 60 Youth
Leather armor, bastard sword, dagger (as opposed to shortsword). He is still mentioned as sometimes using a handaxe of longbow, but also a BATTLEAXE balanced for throwing!

He is said to climb as a 15th level 1e Thief, with no negative modifiers for snow/ice. +3 on saves vs cold.
The Grey Mouser:
Fighter 10/Thief 15/Magic User 3 at peak,
F6/T10/MU3 when mature,
F3/T5/MU3 at youth.
Alignment: Neutral
STR 15
INT 16
WIS 11
DEX 19
CON 17
CHA 17
AC:4 (16 in 3e)
HP: 90 Peak/70 Mature/35 Youth
Leather armor, rapier, dagger balanced for throwing. +3 to hit with any rapier he has had for over two weeks (Weapon Focus & Specialization?). He is extremely streetwise (especially in Lankhmar - high Knowledge (Local), and gets +2 to Gather Information, Bargain, and deal with the bureaucracy, there).
SO! Take yer pick! Personally, I find the latter set of stats a bit better, as the WISs are lower...