Yes. The model 77A was made between 1971-78
The Model 77a is a .22 cal swing arm pneumatic rifle. made between 1971-78. Bluebook of airguns list one in Average/good condition to be worth around $100 Plus or minus.
Recommend you find a qualified firearms instructor or a gunsmith and ask for assistance.
There is a very long story behind this question But here is the short version. S&W was purchased by Bangor Punta in 1965, with the help of a former Crosman Engineer the 77A was developed After several moves back and forth from Florida to Massachusetts Bangor decided to sell the Airgun division to Daisy Airgun in 1980 but had dropped the 77A model in 1978. I don't know of any diagrams for the 77A but it is a forerunner of the Daisy Power-line models. I would try to contact Daisy airgun to see if they "may" be able to help. See the related link at the bottom.
These are currently selling between 60 and 225 dollars depending on condition, if it has the springfield address, box, manual, in perfect working order, etc. If you do a search on gunbroker.com or (see the link below ) you will see some current and recently sold models with pictures to compare your to.
Take it to a gunsmith
Usually between $80 on the low end to $125. This is in the Southeast region
Made by Savage Arms of Chicopee, Mass. 1953 tru 1971
prime because it ends with a 7
http://www.e-gunparts.com/products.asp?chrMasterModel=089Zz77A&MC= PARTS LIST. FOR SCHEMATICS, SEE THE SITE AT NUMRICH - ABOVE Try gunpartscorp.com
Yes because it has more than 2 factors
http://www.savage99.com/data_sheets.htm Go here for the diagram-research fee is $4,00 but worth it!!! Happy Hunting!