There are two ways to look at this piano; 1) as a historical piece and 2) as a musical instrument.

From the historical perspective there are two ways to go.

1. It's definitely an antique and antique value is based on original condition with some cleaning and restoration of original parts including finish. This piano has been refinished which has decreased it's antique value whatever that might be.
2. Restore it to it's original beauty and condition by refinishing and replacement of parts trying to match the state it was in when new. This would be a good choice considering the antique value of square grand pianos is limited.

From a musical standpoint the main considerations would be:

1. Understand the limits of the square grand in regard to repetition. This may not be an issue for most people. A square grand in good working order will play very nicely and have a good tone.
2. Realize that the best function would be attained by having all moving parts in the best possible condition to realize it's full potential and anything less that that is taken into consideration as to playability and durability.
3. Sound quality is largely a result of the hammer string relationship. The strings & wire having been replaced recently greatly improves the sound transmission. The hammers in worn condition will impart a somewhat dull and uneven sound because the strike point is a flat surface rather than more pointed. This difference can be illustrated by knocking your knuckles against a surface then as your knocking roll your fist back to hit more with the fleshy part of your fingers. Rolling between the knuckes and fore part of your fingers the difference can be heard. The pointed knuckle hit produces a clearer even tone l whereas when you begin to roll your fist back to use more of the fingers the hit can be uneven with a thud quality. New or resurfaced hammers could improve the pureness of tone. The wear of the hammers is substantial and might call for hammer replacement for the best result considering the large amount of felt that would need to be removed.

There are three options for these hammers:

1. Remove the leather and reshape hoping for a good crown and weight with the chamfered corners and wear considerations. Then install new leather on the crown.
2. Remove the leather and reshape as above and do not install leather. This would leave a hammer that could be voiced more easily. Both option 1 & 2 would require replacing bad hammers in the high treble. This option saves on the cost of labor and parts for the leather installation. It also would involve a considerable amount of felt removal which will affect tone and feel or touch.
3. Install a set of new hammers with or without leather added to the crown in the tenor and treble. This is the more costly option and adding the leather increases the cost even more.

A drawback to using the leather is the limited ability to voice the hammers to the desired tone after the leather is installed. Square grands were made in two ways; Leather on the hammers from about middle C and up and with leather on just a few hammers in the extreme treble.

The best result for musical tone and versatility would be to use hammers without leather except for maybe a few in the high treble to reduce wear.

Below is a link to a video showing a method for square grand hammer replacement.