FIR analog low-pass filter?
You have to clearly define what you mean by an "analog FIR filter". "No poles" is not correct because (discrete-time) FIR filters do have poles; they are just all at the origin of the $z$-plane (for causal FIR filters). Note that filters without poles do not exist. Take as an example the discrete-time transfer function

$$H(z)=1-az^{-1}\tag{1}$$

with a zero at $z=a$. Obviously, $H(z)$ has a pole at $z=0$. Similarly for 

$$H(z)=z-a\tag{2}$$

which also has a zero at $z=a$, but a pole at $z=\infty$.

If you mean transversal filters implemented as a tapped delay line, then you can find analog versions of it, see e.g. this paper.

If you literally mean a filter with a finite impulse response (FIR) then, technically speaking, such a thing does not exist in the continuous-time world. But of course, any stable system has an impulse response that decays sufficiently fast such that for practical purposes it may be considered as zero (or unmeasurable) after a certain time. The discussion if such a system should be considered as FIR or not is moot.