Google reports:

The Employer Identification Number (EIN), also known as the Federal Employer Identification Number (FEIN) or the Federal Tax Identification Number, is a unique nine-digit number assigned by the Internal Revenue Service (IRS) to business entities operating in the United States for the purposes of identification.
Employer Identification Number - Wikipedia
https://en.wikipedia.org/wiki/Employer_Identification_Number

Are EIN numbers public?
If you are a registering as a business, the Employer Identification Number is public information. If you are an individual registering as a business and providing your Social Security Number (SSN) as your EIN, it will also be viewable by the public, but will be referred to as an EIN, not a SSN.

====================

To minimize accounting and possibly also income taxes, I believe it to your advantage that
the assets you inherited from Marion be idedntified for IRS purposes not with a separate EIN
but with your social security number.