Cant see Steinway serial

[internut]

I have an old family upright Steinway that was purchased by my Grandmother back in the early 60's.  It has been a bit neglected but sounds good still.  It is an upright and I measured from the floor and the top of piano sits at 53 3/4 inches from the floor.  The top does not fully retract so I can not see the top of the Cast Iron plate for the serial like all of the websites say to do.  There are two numbers I found on the bottom of the cast iron plate when I removed the wood down where your feet are.  They are as follows:

71.11/91   and  just below that number   2845

The unfortunate thing is that my aunt had it and she painted it (poorly) except she didn't paint over the
steinway Logo...   anyway... any help identifying would be great.

Scott