It depends from which point you watch SMS message. SMS PDU lies on top of MAP protocol.
When you send SMS message, phone puts recipient number in TP-Destination within a PDU, when you receive SMS message, there is no recipient number anywhere. The reason for this is how SMS works. When someone sends you SMS, GSM network on his side request SRIsm message for you, that means his HLR will try to find you either in his home network, or through your home HLR. The response from HLR is IMSI number (your SIMcard) and VLR/MSC number, to where sender network must send SMS. In second packet, which is actually SMS message (Forward-MT), therefore is only your IMSI number. Since you have dual SIM, you can try to find based on this number, to which SIM card is SMS destined. Note that IMSI number is not part of the PDU but rather lower MAP protocol.