The Frontier mowers are (depending upon the year of manufacture) built by Woods (my 72" RFM is a Woods), BEFCO and others.
My Frontier/Woods has the bushing kit installed to fit the iMatch hooks. The 3PH attach frame, when hooked on the iMatch, is fixed. The deck will pivot around the lower pins a bit, and there will be chains running aft from the uppr 3PH attach frame to near the aft section of the deck, rather then solid metal straps.
Sorry, I don't have pictures of my mower on this computer, but it looks just like a Woods PRD7200 with the exception of the modifications listed above.
How about posting a picture? One close up showing the 3PH frame in it's entirety would help.