We can see the document signature from the screenshot of the deepvault in the block 121284 on the blockchain, here have a look:
{
"hash" : "34adfbfc534ad3d3cfb8d6898463702e0ebfe4d3265e1d0b0bc737f75e0b98c0",
"confirmations" : 8319,
"size" : 664,
"height" : 121284,
"version" : 6,
"merkleroot" : "01a4ee7d52dcf12499724671b2691977c6d26a323bf8b86c8fc162d93bd0e4ed",
"mint" : 5.10712328,
"time" : 1506726780,
"nonce" : 0,
"bits" : "1d01854c",
"difficulty" : 0.65758579,
"blocktrust" : "a8583335",
"chaintrust" : "10aedd31452104c4",
"previousblockhash" : "5e566acee5c20471ec9dbc06081e141edccc8362cfc93654c233856aad5919d8",
"nextblockhash" : "000000000001a3e50307028f47c96163433e6c3a69e8908e50b8f9af07fc3de8",
"flags" : "proof-of-stake",
"proofhash" : "000026237f815fa781ecb9ede56136b96ed26c8a00b16f094b10e56eeacf88bc",
"entropybit" : 0,
"modifier" : "165adea85135ec47",
"modifierchecksum" : "4f87d5c7",
"tx" : [
"649973c0d0fef9a7a74def3a495a47102a70f5c82aee83eca2c0ec89c91afcf9",
"26b5a80af64178b28546a08312483b797d875b6b9707203dfbcd1ab498e25271",
"1118f596b8f0a8d05360b50a7c9be1643b4c5d4d9aeed9f5d927475b581d8c94"
],
"signature" : "3045022100f9ed08a5035f3f2aad32fcc93c74bfbaf14d5081899a081ab45b8f968bbc8c1102200 aa6eb4a8cef8cf308748fb784a363e1131f55a63f798690f8963b7dc6d643d6"
}
Looks like the document signature is 3045022100f9ed08a5035f3f2aad32fcc93c74bfbaf14d5081899a081ab45b8f968bbc8c1102200 aa6eb4a8cef8cf308748fb784a363e1131f55a63f798690f8963b7dc6d643d6
No, this is a normal proof-of-stake transaction.