First steps in introducing the perk system were taken in Tour 14 (March 2001), F4UC was perked in Tour 16. N1K had been in game before that, the La-7 was introduced in Tour 14.
This is the complete planeset of tour 15, just before the F4UC was perked one tour later:
A6M5b
Ar 234
B-17G
B-26B
Bf 109F-4
Bf 109G-2
Bf 109G-6
Bf 109G-10 (K-4 today)
C-47A
C.202
C.205
Chute
empty
F4U-1C
F4U-1D
F6F-5
Fw 190A-5
Fw 190A-8
Fw 190D-9
Fw 190F-8
Gunner
Ju 88
La-5FN
La-7
Lancaster III
M-16
M-3
N1K2
Ostwind
P-38L
P-47-D25
P-47-D40
P-51B
P-51D
Panzer IV H
PT Boat
SeaFire
Ship Gunner
Spitfire Mk IX
Spitfire Mk V
Ta 152H
TBM-3
Tempest
Typhoon IB
Yak-9T
Yak-9U