windsreen

I had a chip repaired by Auto glass 1 week on the repair fell out. A technician now comming to see if it is repairable. Chip is about size of a 5p and deep. Maybe a replacement windscreen .Can i insist on a Merc OEM windscreen or are the pattern ones as good??

I got a stone chip over the weekend just next to the drivers door piller, now I have a split in the screen about 6 inches long. Autoglass are coming out later today to fit a new one, any tips on how I can tell its a Mercedes original screen and not some inferior third party product. Thanks...