There seems to be a mistake in verification outputs for "interface queuing" in the solutions guide.
With legacy FRTS configuration, then yes output is the same - dual FIFO queue. But on R4 queueing on interface is WFQ.
R5:
Rack1R5#sh queueing int s1/1
Interface Serial1/1 queueing strategy: priority
Output queue utilization (queue/count)
high/411 medium/0 normal/1154 low/0
Rack1R5#sh int s1/1
Serial1/1 is up, line protocol is up
Hardware is CD2430 in sync mode
Internet address is 155.1.45.5/24
MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY, loopback not set
Keepalive not set
LMI DLCI 1023 LMI type is CISCO frame relay DTE
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 1313/0, interface broadcasts 1312
Last input 00:00:06, output 00:00:07, output hang never
Last clearing of "show interface" counters 01:43:16
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: dual fifo
Output queue: high size/max/dropped 0/256/0
Output queue: 0/128 (size/max)
<skipped for bravity>
R4:
Interface Serial1/1 queueing strategy: fair
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/1/32 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 96 kilobits/sec
Rack1R4#sh interface s1/1
Serial1/1 is up, line protocol is up
Hardware is CD2430 in sync mode
Internet address is 155.1.45.4/24
MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY, loopback not set
Keepalive not set
LMI DLCI 1023 LMI type is CISCO frame relay DTE
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 1348/0, interface broadcasts 1344
Last input 00:00:02, output 00:00:02, output hang never
Last clearing of "show interface" counters 01:48:49
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Tom