The manufacturing and stitching is consistent with originals I've seen. Even the mismatched colors of the canvas. Where the rust-stain is, could very well be from another frog-button touching it, if it was bundled or in a box. You might want to check the stitching for synthetic thread, but it looks good to me, just looks VERY new... If it is original, then it came straight out of a time-capsule
Thanks so much for the helpful information. I sure hope this tropical frog is a good one ! If it is, I doubt if there are many, if any, others in this condition. I agree, it sure looks awfully new for something so old.