Is he bluffing?

I was at a table today when this really tight player and I ended up in a hand against eachother, now, this dude had set the table image up real nice, only came in with premo hands, and never bluffed, but in this hand against me, he did something that he never does, A)raise all in, on the river, I say this because he usually goes for a value bet, and when someone reraises him then he pushs, or rereraises them. But at the same time, he likes to see flops, and if he hits he sticks like glue to the flop, What I mean is like say, someone raises him, and he happens to call, if the flop comes A/5/9, rainbow, and you raise, he's on you like "white on rice", so is this a bluff, or is it not a bluff that's the question?

PokerStars Game #19510937041: Hold'em No Limit ($0.05/$0.10) - 2008/08/10 - 13:53:35 (ET)
Table 'Jeffers' 6-max Seat #4 is the button
Seat 1: GrO NiCo7800 ($5.60 in chips)
Seat 2: FunkyBöhmi ($2.90 in chips)
Seat 3: LokoIvan ($19.10 in chips)
Seat 4: twicknsisted ($8.45 in chips)
Seat 5: abdi122 ($12.40 in chips)
Seat 6: buzze_stgt ($9 in chips)
abdi122: posts small blind $0.05
buzze_stgt: posts big blind $0.10
*** HOLE CARDS ***
Dealt to abdi122 [Ts Th]
GrO NiCo7800: folds
FunkyBöhmi: calls $0.10
LokoIvan: folds
twicknsisted: calls $0.10
abdi122: raises $0.30 to $0.40
GrO NiCo7800 leaves the table
buzze_stgt: folds
FunkyBöhmi: calls $0.30
twicknsisted: calls $0.30
*** FLOP *** [5c 4d 6s]
abdi122: bets $1
FunkyBöhmi: folds
twicknsisted: calls $1
*** TURN *** [5c 4d 6s] 6♣
abdi122: bets $2.10
twicknsisted: calls $2.10
*** RIVER *** [5c 4d 6s 6c] 5♥
abdi122: checks
twicknsisted: bets $4.95 and is all-in

Ok from my point of view I would say that he wasn't bluffing.
The bet of 2.1 that you made the previous card made him push allin, thinking you had a good hand to call.
Maybe he was bluffing indeed. You can never know. You'll have to ask him :P

I know the answer becuase I ended up calling him just wanted to see what everyone here thought first that's all

Ah lol ok.
So can you please PM me what he had ?
Thanks.