Help In Identifying These 2 Washington 3 Cent Stamps

I am a Plating novice and since colors are hard to distinguish on this issue I was hoping the members here might help me with plating these two Scott #10 or #11 stamps. I may be way off but I figured if I could tell which plate they were from it may help with the color ID.
I have included (if I do this correct) 2 photos. The 1st are the two stamps I am trying to ID. The second is a scan of 5 which include the two in question. These added stamps are all from one scan which may be of some help.
The date stamp shows Apr 15, but no year and there are no other indicators of age on the envelope.

Informative discussion:
https://goscf.com/t/50804

He is just awesome (expert?):
https://goscf.com/m/4054

See here as well: http://www.stampsmarter.com/index.html

Look under the Features tab for 3-Cent 1851-57 info including colors.

The right stamp is clearly from Plate 4. The left stamp is not so obvious but I think is still from Plate 4. Throwing caution to the wind and identifying the color from a scan, I would say both are shades of yellowish rose red and the usage was in 1856. An 1857 usage is possible but I think less likely.

Thanks to all.

Sinclair, what indicators are you using to arrive at your Plate 4 conclusion insofar as the stamp on the right? Learning moment here for me...

The typical Plate 4 stamp will exhibit a heavily recut bottom frameline, a faint or lightly recut left frameline, and a heavily recut upper label block. The stamp on the right is a classic example.

Thanks bunches Sinclair2010.

I see this now in my copy of Carroll Chases book,"The 3c Stamp of the United States 1851-1857 Issue", page 145-146. I guess I got a bit lost in the Plate four discussion of his in the text.

I found it interesting that the 2 stamps had different shades on the same cover.