First Lager

They only suggest pitching too warm to compensate somewhat for underpitching. Even Wyeast recommends a starter (right on their website) for lagers since they don't have enough yeast in the package to pitch at the proper temperature.

For that yeast strain, here is what they say:
YEAST STRAIN: 2035 | American Lager™

Back to Yeast Strain List

A complex and aromatic strain that can be used for a variety of lager beers. This strain is an excellent choice for Classic American Pilsner beers.

Origin:
Flocculation: Medium
Attenuation: 73-77%
Temperature Range: 48-58F, 9-14C
Alcohol Tolerance: 9% ABV
Styles:
Classic American Pilsner
Dark American Lager
Lite American Lager
Premium American Lager
Standard American Lager

 

Also, directly from Wyeast's website:

Pitch Rate:

Lagers typically have a reduced ester profile and are characterized as clean with discernable malt character. It is very important to recognize that pitch rate is directly related to ester production. Increasing the quantity of yeast pitched is the most effective method of reducing the ester profile in the finished beer. A minimum of 12 million cells per milliliter is recommended to keep esters at a minimum.

One Wyeast Activator pack will deliver about 6 million cells per milliliter to 5 gallons of wort. In order to increase this rate to 12 million cells per milliliter it is necessary to either pitch two Activators or to make a 0.5 gallon (2 liter) starter with an Activator. If a starter is made using a Propagator (50ml package) then the starter needs to be 1 gallon (3.78 liters) to achieve 12 million cells per ml.

Fermentation Temperature:

One of the most common questions we field is, “should I start my lager warm or cold?” The answer depends on how much time you have for your primary fermentation and how clean you want your final beer. The best results will be achieved by pitching at least 12 million cells per milliliter into cold and well aerated wort (48 to 58°F, 9 to 15°C).

 

The thing is with lowering the temperature like that, the majority of fermentation will be done before you even get to 50 degrees. I'd go ahead and do it, but it takes a long time for 5 gallons of fermenting beer to change temperature. That's just one of those things to keep in mind for next time.