Are timestamps in transactions trustable? I need to properly segment transactions by time. Are timestamps in transactions trustable? Can these be forged?

I'm not sure if transaction timestamps are part of the protocol, but I'm particularly interested in the "Received Time" which shows up in blockchain.info . For example, this transaction (api url)

{
   time:1385506952,
   inputs:[
      {
         prev_out:{
            n:2,
            value:50000000,
            addr:"17BPmjqg7mbaWYdff2EjVxra1FBHG4VAN3",
            tx_index:97772745,
            type:0
         }
      }
   ],
   vout_sz:2,
   relayed_by:"127.0.0.1",
   hash:"4054f8170f7fc7c12229a116baead874f22478810b0a7e842aa28403c9b59927",
   vin_sz:1,
   tx_index:99131036,
   ver:1,
   out:[
      {
         n:0,
         value:40000000,
         addr:"1LwmnEn97jcANB68C5BVFQLJJLAm5UTJqW",
         tx_index:99131036,
         type:0
      },
      {
         n:1,
         value:9990000,
         addr:"17BPmjqg7mbaWYdff2EjVxra1FBHG4VAN3",
         tx_index:99131036,
         type:0
      }
   ],
   size:257
}
Transactions do not have timestamps, so the timestamp that blockchain.info displays is whatever time their node received the transaction. The time shown will also change to the time that it was included in a block. In general, it is not reliable to trust the timestamp given for an unconfirmed transaction on blockchain.info as it is entirely dependent on their node.