Federal Hud requirements will not allow exposed cables under a manufactured home, as they must be installed in a sealed raceway system, but it will depend upon what your scope of work is? If you are there just to replace just the meters or the meter cabinet and service on the poles? I would spell this out in your contract. here a trailer park has to renew its license every 4 years, and to do this a HUD inspector has to inspect each hook up, and require any repairs as needed, so I would approach the owners and tell them what you found but leave it up to them and the inspector as what is your responsibility.
Also keep in mind that these have to have 4-wires into the trailer with an insulated ground, under the latest Hud rules a 3-wire can be run to a disconnect outside the trailer, but a 4-wire must be landed in the trailer from this disconnect, if your local codes some how supersedes HUD codes (not sure how) then the 2008 wont allow the 3-wire except for existing, as HUD CFR 24 3280.800 is based upon the 2005 NEC with amendments
You can access the PDF version of CFR 24 3280.800
HERE