Linksys Wired Router :: BEFSX41 V1 Or V2 For Firmware Upgrade 1.52.16.4

BEFSX41 Firmware Version to upgrade, version 1 or 2?
 
I've been using this router since 2006, upgrading the firmware to version 1.52.15 when released in 2007. At that time I think I selected the edition 1 rather than edition 2. Basing decision on the fact that the device had no indication of which model version was correct indicated on the manufacturing labels on the bottom. So I assume edition 1.
 
Is there any way to tell which hardware release I really have? Maybe by MAC address, or Serial number?
 
Have not had any problems with the 1.52.15 firmware version, however, I have seen numerous log entries for the following:
 
2011-03-20 11:45:23 ii=MAX_HTTPSESS2011-03-20 11:45:33 ii=MAX_HTTPSESS2011-03-20 11:45:39 ii=MAX_HTTPSESS
 
and
 
2011-03-20 10:53:09 UDP from 202.103.52.147:5060 to nnn.nnn.nnn.nnn : pppp(my ip address & port) followed by 2 to 10 of the following entries:2011-03-20 11:01:33 500 _upnp_Disable
 
the sending URL indicated as a PRC (Chinese) university with negative traceroute results, nothing really alarming as nothing is getting inside the firewall. Just packets dropped from the senders IP. I am keeping track of the pattern  and activity levels.
 
Will probably just block the whole addy range at the router firewall and PC firewall. AT&T is totally ineffective in blocking this sort of back alley activity.
 
I've seen only one brief and somewhat dated reference to the "ii=MAX_HTTPSESS" entry and will tackle that issue after updating the firmware to 1.52.16, I haven't found any authenticated tech references for this. I can only make some educated guesses on tweaking HTTP settings.