"Inflation rate" is relative to the number of coins in existence. You said it yourself: growth in monetary base.
LTC's current inflation rate is over 5x that of BTC. See here: https://bitcointalksearch.org/topic/inflation-rate-coin-supply-growth-of-major-alt-coins-updated-2013-06-26-227395 .
That rate of inflation is CONSTANTLY CHANGING for BOTH COINS. It's just a matter of how far down the mining curve it is. LTC started Oct 2011 making it 22 months old. It has the same inflation rate as BTC had 22 months after it's launch. Any side by side comparison will always show that LTC has a higher inflation rate then BTC but that ratio is just coincidentally around 4 right now, it has nothing to do with the 4 times greater nominal block rates.
The day LTC started it had a million times the inflation rate as BTC had on that day back in 2011, as time goes on the rates for both coins will decline and the gap both in absolute and relative terms will decline. Years from now BTC will be growing at 1% a year and LTC at 1.1% an insignificant difference. chodpaba has ignorantly concluded (or at least implied) that LTC ALWAYS has a 4x higher inflation rate, and any conclusion drawn from that is going to be flawed. As for what a fair valuation for LTC is I have no comment but at least get your basic terminology right before you post your speculations.