Hello Karl,
That is correct. The LED has I believe had a few changeovers at Labmaker depending on availability. Often these parts seem to go obsolete. The one you have identified (Wurth 15335327CA452) looks like a perfect replacement, in terms of wavelength and current/voltage profile. One difference between emitters is some have a focusing lens and others not. However, given its proximity to the test-tube this may not be supremely important as a large fraction of light will reach the cells regardless.
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