If it just has an orifice in it then it would work either way, just not as engineered. And orifice is like this: (with out the dotted line)
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It drops the airflow capacity. So backwards it would be working with less to start with and , of course, not expand after passing the orifice. Installed the other way, there is more flow to the orifice, then less...So in effect it will work either way, now if there is a one way flapper in there, then it won't hold the vacuum installed backwards. I don't know if it is intended to hold vacuum or not, or to just provide an orifice.

Well I did it. I bought a set of Beru ignition wires from Fastlane. They were just about $65.00 more than Bosch and I figure that I won't have to change them again for years.
They sould be here before the GTG at Enrique's on the 3rd.

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1986 Euro 500SEC "RUF" 9:1CR, "Rose"
1985 Euro 500SEC Cabriolet AMG Widebody
1982 Euro 500SEL "Blue"
2001 Texas Heeler (Aussie/Queensland X) "Sulphie",
2012 Queensland Red Heeler "Squeak"
Best dogs I've ever had.