All original P.F.Magic and Studio Mythos breedz have their ID numbers
where I state in my tutorials and howtos; between the List of everything
that's in the file and the start of the bitmap.  In the case of the 
Labrador, that would look like this in Hex Workshop:

00037616 5F00 5700 4800 4900 4D00 5000 4500 5200 _.W.H.I.M.P.E.R.
00037632 3000 3400 0C00 4C00 4200 5F00 5700 4800 0.4...L.B._.W.H.
00037648 4900 4D00 5000 4500 5200 3000 3500 0000 I.M.P.E.R.0.5...
00037664 0100 0000 4C61 6272 6164 6F72 5370 7269 ....LabradorSpri
00037680 7465 0000 0000 0000 0000 0000 0000 0000 te..............
00037696 0000 0000 4C75 636B 7900 0000 0000 0000 ....Lucky.......
00037712 0000 0000 0000 0000 0000 0000 0000 0000 ................
00037728 0000 0000 FB03 0000 0100 0000 0000 0000 ................
00037744 424D C029 0000 0000 0000 3204 0000 2800 BM.)......2...(.

The number is in the line above BM here, and is FB03.

Now, you've downloaded a hexie and you cannot find the ID number there --
in fact, the bitmap comes directly after the List and looks like this:

00037616 0C00 4C00 4200 5F00 5700 4800 4900 4D00 ..L.B._.W.H.I.M.
00037632 5000 4500 5200 3000 3400 0C00 4C00 4200 P.E.R.0.4...L.B.
00037648 5F00 5700 4800 4900 4D00 5000 4500 5200 _.W.H.I.M.P.E.R.
00037664 3000 3500 424D C229 0000 0000 0000 3604 0.5.BM.)......6.

Well, the reason you can't find the ID is because this breedfile was edited 
using ResHacker.  I can tell this by the position of the ID number, which 
always appears to be shifted to just after the naming area in a ResHacked file.  
So, search for the naming area (look for hex 50004600 as usual), and then 
look at the few lines below it:

00765936 2900 2000 3100 3900 3900 3700 2000 5000 ). .1.9.9.7. .P.
00765952 4600 2E00 4D00 6100 6700 6900 6300 2C00 F...M.a.g.i.c.,.
00765968 2000 4900 6E00 6300 2E00 0000 0000 0000  .I.n.c.........
00765984 0000 0000 0000 0000 0000 0000 0000 0000 ................
00766000 0000 0000 0000 0000 0000 0000 0000 0000 ................
00766016 0500 4C00 7500 6300 6B00 7900 0B00 4100 ..L.u.c.k.y...A.
00766032 5200 2000 5300 7000 7200 6900 6E00 6700 R. .S.p.r.i.n.g.
00766048 6500 7200 0200 4C00 7200 0000 0000 0000 e.r...L.r.......
00766064 0100 0000 4C61 6272 6164 6F72 5370 7269 ....LabradorSpri
00766080 7465 0000 0000 0000 0000 0000 0000 0000 te..............
00766096 0000 0000 4C75 636B 7900 0000 0000 0000 ....Lucky.......
00766112 0000 0000 0000 0000 0000 0000 0000 0000 ................
00766128 0000 0000 7A03 0000 0100 0000 0000 0000 ....z...........

Okay, see where you've got LabradorSprite, then Lucky?  The ID number is a couple 
of lines below that, and in this case is 7A03.

It may be that other resource editors place the ID number elsewhere.  If so,
don't panic; just look for the <breedname>Sprite (in this case LabradorSprite) 
and the default Adoption Centre pet name (in this case Lucky), and you will find
the ID number a couple of lines below it.  Not as simple to find, perhaps, but
once you know what you're looking for it should get easier for you.

In the case of clothes and toyz etc, the same basic idea applies; for instance,
with the Stick toy, search for Stick and after one or two instances of the word 
you'll find you're in the right place, with Sprite_Stick_X1 above it and the ID
number below.

Good luck

Carolyn Horn