Need help understanding a TSB (not tacoma)

I posted a while ago regarding a TSB on my cousin's Corolla. I'm helping him out because he knows nothing about cars. Long story short, the dealer wants 1800 bucks to perform a TSB since he's out of warranty. Our local mechanic was going to do it, but says he can't because the car needs a computer update after the work is done. ECU reflash I assume...
I have a buddy who's a former Toyota tech and he says he can do the work as stated in the TSB, and he also says that it doesn't say anything about an ECU reflash. I am just wondering if we have my buddy do the work, would it need a "computer update"? Would Toyota do the update is someone else did the work, for a fee of course. Here's a copy of the TSB. Thanks as usual.

http://www.toyotapart.com/BRIEF_ENGINE_KNOCK_RATTLE_NOISE_AT_COLD_STARTUP_T-SB-0087-09.pdf

 

No update Drew for this repair.
Hard parts only.

 

Interesting the dealer is charging $1800. Assuming $120/hr shop rate, the labor should be about $830 using the time listed in the TSB. Parts add up to $290 MSRP (before ~20% online discount) on VillageToyotaParts, so about $1100 total.

There is no ECM flash associated with the TSB; just hard parts replacement. If there were, the TSB would typically list the ECM firmware version or P/N.

How bad is the rattle by the way? Seems like a lot of work for a "one-second" rattle.