Greetings Pattye --
Before a specific comment on that trademark, a general (pre-coffee, sorry

) observation:
As Harold has noted, the present problem with dating clocks from Kienzle (or Schlenker-Kienzle etc.) is that there's no considered body of data available. This would be a base that includes various movement designations, sets of catalogues across the years, derived serial number-by-years tables, and so on. It would support information good enough so we would know, for instance, exactly when Kienzle first used rod gongs (not just "after Obergfell in 1899").
Yet this is the same problem we have with *most* other of even the largest German firms, whether Junghans or Mauthe or Kienzle.
To set up such a base would require that someone, or more likely someones -- would adopt the firm and make it their earnest and constant business to gather together every bit of information about the firm and its products. To put together a photo and data bank based upon hundreds of examples, as for example "our" Steve Green (hi Steve!) is doing for Lenzkirch. Or what John Hubby is doing for Becker.
Yet until then....
More specifically (post-coffee, sun coming up

):
Dating Kienzle clocks using "registered by" information -- especially information contained in the Trademark Index is an inexact affair. The main reason is that we know that some of the information in the Index is inaccurate. That it's creaky-hard for some people to accept that this is so doesn't change the fact that it is.
Here's an example we've used in some presentations:
Shown below is a record that I found in a German journal of the time showing that this Kienzle trademark had been registered in 1892. And until 1894, all trademarks were registered -- as this one was -- at the appropriate "local" court (for K, Rottweil).
Also is an entry from the Trademark Index giving 1898 as the registered date for the trademark shown. The Index shows another variant as 1908. So that Index reference might well indicate to someone with that first trademark on a clock that it was "after 1898" at the earliest.
BUT because that 1898 date was in the Index, edition after edition, it's been picked up in other references, repeated again and again, "sold" through websites, and...so it goes.