I wouldn't be hugely surprised by the lack of a mark; of the three small rose bowls I've had through my hands recently, only one was marked 'Reg App' (strangely no 'for' and different to the mark on Pamela's example). The other two both appeared to be late examples with the fine details on the bottom of the bowl poorly defined and further soften by having been heavily sandblasted, no trace of a mark was visible on either. The 13" rose bowls I have seen have invariably been marked, however.
In fact, I've had quite a few unmarked pieces recently, notably a 7000 bird bowl which was almost certainly an early example as it had the original mould detail and was very crisply moulded, particularly in the birds' tail feathers which tend to show a bumpier 'orange peel' effect on later examples. I also have two 8" flanged 6000 flower bowls, one in opalique and one in black which are completely unmarked.