Delurking with a question about moonflowers/morning glories...

I was just wondering. I have a trellis that has morning glories and moonflowers on it. Im not real good at telling the difference between the two leaves-wise but I noticed a bud(it looks like a normal bud for a moonflower) but it is purple. Is this the seed pod? If so how should I harvest the seeds..I would like to restart my own next year and save us the money next year.. Any help would be appreciated.
Thanks :)
Lilygardn

The seedpod of the moonvine will be larger than those of the MGs, and somewhat pointed. Like the MG pod, it will turn brown and somewhat papery when the seeds inside are ripe. Each pod usually containes three or four seeds.

This is what the pods(?) look like? Are these seed pods?
http://www.members.aol.com/lilygardn/moonflowerpod.jpg

Yep Lily, thats Moonflower seed (Ipomoea alba - aka Calonyction)

El Tel