99.99 percent of rineloricaria sold are in fact eigmannis. Loricaria/farlowella/spatuloricaria (especially as of late)/sturisoma are also fairly common in the trade.
I have tried a few times to keep farlowella, they need a lot of space to get around their bodies don't bend ! I find they are also hard to feed...and fragile , but they are awesome wish better luck then I have had...