Hello, I have been learning about stamps, identifying and collecting for 5 years. I am a librarian with a few research skills: cross referencing Scott's catalogues, online grading resources, databases and listening to stamp collecting podcasts- I pre-curse this give you insight to this query. It is not a willy-nilly, fingers crossed guess. I researched as much as I could. I'd like some feedback the grill, cancellation, color...and anything I may have missed, feedback is greatly appreciated.
Here is the front cover (The back of envelope has no postalmarkings, or writing - blank)

1. Is there a grill? Or are my eye deceiving me?

If yes, are the arrows pointing down?

2. Post mark cancelation date - Is it a pre-civil, during or after civil war cancellation?

3. If it is a #85 it can only be rose.
4. 12perf-yes

5. Envelope is a 5 x 3 "calling card" style, smooth thick cream paper, embossed with a W on both front and back.

6. Grading = grading app gives it a G-VG 42; I have no idea.
Thank you, Eliza