PA41 is a fiduciary income tax return and not an inheritance tax return.
The personal representative is responsible for filing the PA inheritance tax return.
From the instructions to Form REV-1500:
"WHO MUST FILE
An Inheritance Tax return must be filed for every decedent who
has property which is or may be subject to tax. You must file a
return if you are:
(a) The personal representative of the decedent's estate.
The return must disclose property of the decedent administered
by the personal representative and additional property,
which is or may be subject to Inheritance Tax, of
which the personal representative has or acquires knowledge.
(b) The transferee of property, if no personal representative
is appointed or if the personal representative does not
file a return, or if the personal representative files a return
but does not include the subject property...."
So, the representative must file but if the representative does not file or does not include inherited property then the beneficiary must file on that subject property.
The REV-1500 Inheritance Tax Return - Resident Decedent is used for this purpose.
The annuities that represent a return on an investment which are taxable would be reported on REV-1510 Schedule G of the REV-1500 forms.
You can confirm with the personal representative that REV-1500 was filed and that the annuity was on Schedule G and the tax was, or was not, paid.
If you can not get confirmation from the personal representative you would need to contact the Register of Wills Office in the county where the return was filed. It is not clear how long after filing that those records would include the return.
Please ask if need more discussion or clarification.