Contacting NVC for AoS with in USA

I got my I-140 approved a year ago. I got NVC receipts to pay consular processing. I wish to file for I-485 with in US and sent lettesr to the NV, both for me and my wife. I only got the USPS register post return receipts. Does it enough to show as proof that I contacted NVC?

You may use it as proof. I am trying to understand the context, can you share why you want to use that proof ?

Thanks a lot for the reply and apologies to get back to you. I have I-140 approved on EB1A and going to submit I-485 next month. While on I-140, I opted to choose NVC processing and now, I am filing for the AoS with in the US. Since there is a suggestion to update the NVC if going for AoS, I sent two letters ( for me and my wife) to the NVC about our intentions to file AoS, with USPS registered post- with signature proof card. My question here is Do i need to send these NVC signed-USPS cards along with my I-485?