Your approved I-140 has no relation to your wife's 485...
Let's say, today you got your I-140 approval notice....and let's say you don't file your I485....then how can USCIS accept I485 ....without the primary filing first?
I would say your I485 filing is the proof that USCIS can use as proof of filing for dependents....I guese, may be you could use the photocopy on back of the check deposited by USCIS (which shows the receipt number) as one possible proof of filing...but in this forum, I am hearing that checks are getting deposited one month after submission...due to the frontlog of 485 submissions
