Types of leather on Givenchy bags?

I'm eyeing my first ever Nightingale and can't decide between lamb and goat. Is goat marginally or significantly heavier than lamb? I'd prefer a super slouchy, super soft bag and will be going with the small size. Help?
 
update to above:

goat - smooth still, but not as soft as the lamb; on the matte side, and quite sturdy feeling.

may be my new go to leather!

IMG_9087.jpg

Hi I bought a preloved Antigona in Japan. Can u help me by pic what type of leather it is? Size is medium and zipper is still RACCAGNI. Is this calf or goat? Thanks in advance[emoji6]