Quick question about SHSH Blobs

hi all, im new here!

i wanted to jailbreak my friends ipod it is/has
firmware 4.0
mc model
8 gig
3rd gen (i think) could also be 2nd gen

im trying to downgrade the firmware to 3.1.2 or 3.1.3 to jailbreak it
i understand that to downgrade i need the SHSH blobs from when the ipod had 3.1.2 firmware ( it did at one point)

i also have an ipod touch
32gig
2gen
Mc model

the diffrence is that i have firmware 3.1.2 and mine is already jailbroken.

assuming i could get the SHSH files... could i use the files from my ipod touch to downgrade his ipod touch

(also, way back when my friend first got his ipod he synced with my itunes library and with a copy of my saved ipod stuff, the ipod still has the same files, same name, and same settings)

thanks for any help with this.

 

thanks!. And if you don't mind me asking, how do you know its a second gen? i could never tell the difference between 2nd and 3rd gen