[This particular model was made for the Spiegel Company in Chicago in 1965 and there were only 4,264 made. I am having trouble finding a value on this gun.]
The reason for your difficulty lies in the fact that different guns, from many different manufacturers, have at one time or another been specially embellished to honor/commemorate one organization or another.
Some were generated by the respective manufacturers, while others were comissioned by the particular company "honored".
These are guns like the one you have, Wild Turkey Foundation guns, various auto supply chains, etc, etc.
They are all usually valued at about the same as a like-condition unadorned model - and sometime much less - by parties uninterested in the honoree.
Some very few are valued higher - but usually only by members of the company/party so honored.
IOW, The highest value for your particular Marlin might only be realized by marketing it in the Chicago area to persons formerly associated with Speigel's.
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