Thanks, @rjs .
To add some detail, I was originally confused b/c when I printed out the amended federal 1040X, TurboTax also included the original 1040 but it was updated with some of the info that was on the amended return.
But the following link says that I'll only need to include that 1040 if the IRS requests it. I've included it here for others that come across this post to add some additional context.
https://ttlc.intuit.com/community/after-you-file/discussion/when-mailing-my-1040x-amended-return-do-...
"No.
You do not need to include the Form 1040 with the corrected numbers unless you are instructed to do so after filing your amended return.
Please see the following excerpt from the instructions on what you may need to include with your 1040-X."
