To get a list of HP Serial numers run the following Powershell script. Place the servernames/ipaddresses you want to check in the serverlist parameter.

#
# Get HP Serial Numbers from server text file
#
# Written by Bastiaan van Leeuwen
#
# Change $serverlist parameter to the right text file

$serverlist = "d:\script\servers.txt"
$username = Get-Credential domain\user

foreach($server in get-content $serverlist)
{
gwmi win32_systemenclosure -computer "$server" -credential $username –ErrorAction SilentlyContinue | 
select __SERVER,serialnumber
}