In a note to clients issued late Wednesday, Munster suggests that the looming map wars — in which Apple is reportedly poised to replace Google Maps as iOS’s default mapping app, and to which Google has responded by beefing up its 3D mapping imagery — is not likely to tip the balance one way or the other.

If Apple does drop Google Maps from the iPhone and iPad, Google will probably stick around, turning it into stand-alone app on the App Store. Munster believes it could quickly overtake Google’s other free iOS apps (Search, Gmail, Google+, Translate).

Google has made it clear that it views its presence on mobile devices as an important strategic beachhead, even if the revenue it brings in today is relatively small.

Munster estimates that Google will generate about $4.5 billion in gross mobile revenue in 2012, the lion’s share ($4 billion) from search ads and the rest ($500 million) from display. He believes that iOS is likely to remain the biggest or close to the biggest source of that revenue, generating roughly 40% of the total (or $1.6 billion). Assuming Google keeps half (after subtracting so-called acquisition costs), iOS would generate about 2% of Google’s total revenue in 2012.

Bottom line, according to Munster: “We do not expect any material impact to these assumptions if Google Maps were to no longer be the default mapping application on iOS.”