Identifying wallet file among soup of recovered .dat files
I quickly verified my system, here is what might help you to identfy:

$ file wallet.dat 
wallet.dat: Berkeley DB (Btree, version 9, native byte-order)

$ file blocks/blk00233.dat 
blocks/blk00233.dat: data


and if you have a hexdump tool (this here should work on Unixoide type systems):

$ hexdump -C wallet.dat | more
00000000  00 00 00 00 01 00 00 00  00 00 00 00 62 31 05 00  |............b1..|
... many, many zeros, and from time to time some numbers :-)
00001ff0  04 00 01 00 00 00 02 00  04 00 01 6d 61 69 6e 00  |...........main.|


whereas blooks are full of numbers...

$ hexdump -C blk00233.dat | more
00000000  f9 be b4 d9 1f ad 06 00  02 00 00 00 f2 50 36 7e  |.............P6~|
00000010  af 4f e8 37 f7 2f 0f db  8b cf a1 3e 34 73 0d eb  |.O.7./.....&gt;4s..|
00000020  f9 ca 1d 05 00 00 00 00  00 00 00 00 76 89 01 91  |............v...|
00000030  46 d5 24 ed 48 bd ff ed  68 77 3e ca 28 0e b8 74  |F.$.H...hw&gt;.(..t|
00000040  30 73 cb aa 0e 32 d9 91  9f a9 ed 73 b1 d2 e5 54  |0s...2.....s...T|
00000050  87 bb 18 18 90 7d 19 02  fd c6 02 01 00 00 00 01  |.....}..........|
00000060  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*


as you don't want to do this for each and every file, you may want to tell your system what to do:

for i in *.dat; do file $i; done