I just lost my whole response to you because some stupid thing went wrong with my computer!...Here goes again.
Mel: don't hit the recall button yet! The issue is not degrees of conservation framing; it is understanding the requirements, IN CONTEXT.
The concern over art's proximity to wood is in the context of RAW wood, in particular, the art's proximity to the lignin and tannin (tannic acid) in raw wood, and their possible adverse effects upon the artwork. This same concern applies equally to the raw, unfinished rabbet in wood mouldings!
Fillets have multiple coatings on them to prepare the raw wood for its final decorative finish. If all of these coatings are benign, intact, and non-porous, then the concern is alleviated, as is the potentail for damage. However, since we do not know, with any degree of certainty, the condition and characteristic of the finish on the fillet (particularly on the verso, the face closest to the artwork) it would be prudent to seal that surface with a suitable agent. Recommended two coats of waterborne urethane, and don't use the cheap stuff! Use the stuff that has a high percentage of urethane plastic in it. Let it dry well.
The CCI reference that I posted previously has a discussion concerning lignins' effect on fine art. It seems that the jury is out on this one,again!
Please understand that deleterious effects of acids, lignins, tannins, pollutants etc. on artwork is only concerning in degree, and to a very large extent regulated by the presence of excess moisture levels. Protect the art from high U-V exposure, high temperatures, high moisture, sources of potentially harmful materials (e.g. bargain-basement matboard), provide a safe environment (appropriate mats and mount board) reduce the amount of time that the artwork is exposed to the harmful things in life, and you will have done your job.
... by the way, you can check with CCI on the best way to mount those mocassins. Tanned? Untanned? They are a natural animal product and therefore do have their own sets of problems. Now, are they naturally acidic or are they...
Don't go overboard with this stuff, or you'll wind up paranoid.
[This message has been edited by Orton (edited 09-30-98).]