From my experience, not all bulbs have their numbers (at least numbers you can easily use to buy replacements in the USA) printed on or stamped into them.
Case in point, the 1157s that came on my new 900 LT only have the wattages (P21/5W), the voltage, and two numbers -- 6P 13 and 37R(E6)214 -- which with my lack of knowledge, don't tell me to buy 1157s.
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