This seems to be the year of Beistle. Prices for many vintage items issued by this still-going-strong American company have been in the stratosphere so far this season, and there is no reason to expect that will not remain the same for this combo. Although the envelope surfaces regularly, seldom does it do so in this condition. Listen, the envelope is large and easy to ruin, accounting for how relatively few of them that still exist in this condition from 1935. Guide value is $175 but I won't be at all surprised if this brings significantly more dollars than this - given that this seems to be Beistle's season to really shine. (I sure am glad that I have specialized in collecting this company's output for several decades.)
09/22 Update: The forecast was correct - this combo brought a strong $256.77.